When Stromatolites Were called Concretions, Devil’s Pots, Snow-shoe Tracks and Cannon Balls

    "The paradox presented by stromatolites is conveyed by Ginburg’s (1991, p. 25) impish comment that “few observers have any difficulty identifying archetypical stromatolites... yet defining stromatolites is controversial”.  This is like saying that everyone knows what stromatolites look like, but no one can agree what they are.”
    Robert Riding, 2011, The Nature of Stromatolites: 3,500 Years of History and a Century of Research
   
The premise for this posting is that while most current geologists can put the name stromatolite to a layered structure, either domal or columnar in form, that they realize was formed by sediment trapped and precipitated by algae, those structures were initially identified as concretions (or by a descriptive name)  and the identification of the structure as a concretion (or by another name) carried the implication that it was inorganic rather than organic.

Below I mention a number of early papers which identified structures as concretions, and mention a few with interesting names for the structures.  I also mention a few early papers that have been overlooked.   I deal first with references to structures in Precambrian rocks of the Canadian Shield and then with structures found in Paleozoic rocks in the Ottawa Embayment.  The only concretions mentioned that I cannot confirm are stromatolites are the ones reported from near Vermilion Lake.

The Gunflint Stromatolites

The stromatolites in the Thunder Bay area of Northern Ontario have been written about extensively.  The Gunflint stromatolites (also known as, the Animikie stromatolites) are deservedly well known, as are stromatolites from the nearby Sibley Formation.   In addition, the discovery of microbial nanofossils in cherts associated with the Gunflint formation stromatolites advanced our understanding of life in the Precambrian.   

Below is a photograph of small (6 cm x 5 cm) slab showing stromatolites from the Gunflint formation.  The specimen is comprised of red, white and black chert.

This slab and other specimens were obtained on a collecting trip to Northern Ontario last year by Ed Hinchey and his wife  –  the proprietors of the Rox Rock Shop on Bedford Street in Westport, Ontario – and are being sold in their shop (along with slabbed specimens displaying stromatolites from Minnesota and Australia).    (https://www.facebook.com/ROXRockShop/)

The above specimen was obtained from a locality in an old mining district just south of Kakabeka Falls, which is on the Kaministiquia River,  about 20 kilometers west of Thunder Bay.
Ed Hinchey told me that he collected numerous specimens from this locality that he will be cutting into slabs with a rock saw and selling through his shop.   By chance, the locality where Ed Hinchey and his wife collected the specimen shown in the above photograph would be within twenty-five  kilometers of where W.E. Logan, Alexander Murray and Robert Bell reported structures that are mentioned below.

Hofmann,  1969, Stromatolites from the Proterozoic Animikie and Sibley Groups

A leading paper on the Gunflint stromatolites and Sibley  stromatolites  was written by Dr. Hans J. Hofmann of the Geological Survey of Canada:
   
Hofmann, H. J., 1969, Stromatolites from the Proterozoic Animikie and Sibley Groups, Ontario,
Geological Survey of Canada, Paper 68-69.  85 pages, including  9 figures and 22 plates.
http://wmsmir.cits.rncan.gc.ca/index.html/pub/geott/ess_pubs/102/102252/pa_68_69.pdf

In that paper Dr. Hofmann mentions (at page 5)  that:

 “Nearly a century has passed since Robert Bell of the Geological Survey of Canada reported “small coral-like siliceous concretions and vertical cylinders of chalcedony, transverse sections of which shew fine concentric rings resembling agate” from an area just west of Fort William (Bell, 1870, p. 324).  He was referring to structures now called stromatolites, in rocks presently identified as part of the Gunflint Formation.”

In 1847 Logan  and Murray Report Concretions on the Kamanistiquia River and along the Shores of Lake Superior: – an early  Report of the Gunflint Stromatolites

Authors relying on Hofmann have understood his reference to Bell’s paper as being the first written on the Gunflint stromatolites.   However, over two decades earlier W.E. Logan and Alexander Murray of the Geological Survey of Canada had examined the British Shores of Lake Superior and described structures that we now call stromatolites.  Mr. Murray’s attention was devoted to the examination of the Kamanitiquia River and Michipicoten River, while Mr. Logan examined the mining claims and the coast generally.   Both reported on the structures that we now call the Gunflint stromatolites.
   
Here is part of Mr. Logan’s report:   

“In the vicinity of disturbed parts the chert sometimes passes into chalcedony and agate, and small cracks are filled with what appears to be anthracite. Some of the chert bands appear to be made up of a multitude of minute, irregular, closely aggregated sub-globular bodies, floating as it were in the silicious matrix. Anthracite seems to be present in the centre of some of these, leading to the supposition that the color of the black chert, even where these shapes are not detected, may be owing to the presence of carbon. In some parts of these oolitic chert layers, small blood-red jaspery spots occasionally become interstratified with the black ; ...
   
Higher in the formation, argillaceous slates become interstratified with argillaceous sandstones in such an altered condition that it is often difficult at first sight to say whether the latter may not be trap layers. The sandstones are sometimes slightly micaceous, and they are rather lighter
in color than the slates or shales; and while the slates sometimes exhibit the structure called cone in cone, the harder bands display spherical concretions varying from a few inches to two and even six feet in diameter. In some parts of the vertical thickness calcareous layers are occasionally interstratified among the slates, but few of them are pure enough to be  entitled to the appellation of limestone.” 

Logan, W. E., 1847, Geological Survey of Canada, Report of Progress for the Year 1846-47, at pages 13 and 14.

Here is part of Mr. Murray’s report on a calcareous, hard argillaceous slate alternating with beds of chert along the Kamanitiquia  River :

“Spheroidal concretions of singular uniformity, and sometimes of large size, are disseminated
through all that part of the formation over which the river passes, and they are more conspicuously displayed among the more shaly portions of the rock. A little above the lowest rapids there is a great accumulation of these concretions, which have been known to the fur-traders for many years under the title of the Devil's Pots. Some of these are six feet in
diameter, with a thickness of two feet, and they are found of all sizes down to that of a pigeon's egg. They are usually more convex on the top than on the bottom, bearing a strong resemblance to the stones used in the game of curling. The lines of lamination are distinctly visible in these
concretions; and in some instances, when not removed from the parent bed, the lines could be traced from the concretion to the partially enclosing rock. They are always highly charged with iron pyrites, and their weight, when they are moderate in size, is in great consequence.”

Alexander Murray, 1847, Report of Andrew Murray,  Assistant Provincial Geologist, Addressed to W. E. Logan, Provincial Geologist, in Logan, W. E., 1847, Geological Survey of Canada, Report of Progress for the Year 1846-47, at page 54
                       
Both of those reports were repeated verbatim in Logan, W. E., 1863, Geology of Canada, Geological Survey of Canada, Report of Progress from its Commencement to 1863, 983 pages,
at pages 68 and 69.

Logan’s and Murray’s reports of concretions do not appear to have been widely circulated. 
A very brief summary of Murray’s report appeared under the heading “The Kaministiquia to the Height of Land.  Mr. Murray on the Valley of the Kaministiquia,” in  Papers Relative to the Exploration of the Country between Lake Superior and the Red River Settlement, Presented to Both Houses of Parliament in 1859, where it was mentioned of the slates at the Grand Falls, the rock “shows many of the spheroidal concretions charged with iron pyrites noticed by Mr. Murray in his report.”

The 1870  Report of Dr. Robert Bell

Robert Bell of the Geological Survey of Canada appears to have been the next to remark on the Gunflint Stromatolites.   In his geological report of the country lying on the north-western side of Lake Superior Robert Bell made three references to the Gunflint Stromatolites: 

“The shaly portions hold regularly formed spheroidal concretions of various sizes. ... The shales are seen on the lower part of the Kaminitiquia River, especially at the Grand Falls, and along the coast of Lake Superior, between Fort William and Pigeon River...” [Page 319]
       
“At about twelve miles south-west of Fort William, and two or three miles north-west of the Shore of Lake Superior, opposite Pie Island,  a lake occurs, called Ka-zee-zee-kitchi-wa-ga-mog.  ... Sucker Brook, which discharges its waters into the lake, rushes down over underlying almost  horizontal shales.   These contain numbers of singular spherical concretions, similar those observed by Sir W. E. Logan in the shales of the same formation, in the bed of the Kaminitiquia.” [Page 322]


“three-fourths of a mile north of the town-line of Neebing, nearly horizontal calcareous beds occur, containing small coral-like silicious concretions and vertical cylinders of chalcedony, transverse sections of which shew fine concentric rings resembling agate.” [page 324]

Bell, R. 1870, Report of Mr. Robert Bell, Geological Survey of Canada, Report of Progress from 1866 to 1869, 313-364  at pages 319, 322 and  324. Dated at Montreal, May 23, 1870. 
http://archive.org/stream/annualreportgeo15canagoog#page/n10/mode/2up

Interestingly, H.J. Hofmann, who wrote the seminal paper on the Gunflint stromatolites, referred only to Robert Bell and not to Logan and only to Bell’s above third quote mentioning coral-like silicious concretions.   

The 1889  Report of Dr. Robert Bell - Bombs, Boulders and Kettles

In 1889 Dr. Robert Bell authored a report of a royal commission that was later released as a separate publication, in which he discussed the Animikie strata, mentioning that “Lenticular and spheroidal concretions of various sizes, called also bombs, boulders and kettles, are common throughout the black shales of this division.”

Bell, Robert, 1889, The Geology of Ontario, with Special Reference to Economic Minerals, published at Toronto by Warwick & Sons, 72 pages, a reprint of the Ontario Royal Commission on the Mineral Resources and Measures for their Development.

Commander H. W. Bayfield, Royal Navy, and Globular Concretions

It is possible that there is an even earlier reference to the Gunflint Formation stromatolites than Logan (1847).   Many will be aware that both John Jeremiah Bigsby, M.D.,  and Commander H. W. Bayfield, Royal Navy, had  explored the geology of the Thunder Bay area two decades before Logan, and that each published written reports of their findings.   Bayfield reported on outcrops on islands at the east end of “Neepigon Bay” and mentioned greenstone that becomes more or less slaty, sometimes showing signs of stratification, and that it “sometimes contains globular concretions not unlike those observed in the greywacke of the St. Lawrence.”   It is hard to tell what he meant by ‘globular concretions’.   Interestingly, Hoffman (1969) included a map in his paper on which he plotted the location of Animikie (Gunflint) stromatolites and Sibley Formation stromatolites, and shows Gunflint stromatolites at the east end of Nipigon Bay.    Bayfield’s ‘globular concretions’ could be stromatolites. 

Bayfield, H. W., 1829, Outlines of the Geology of Lake Superior, Transactions of the Literary and Historical Society of Quebec, Volume 1, pages 1-43 at pages 20-21
       

Was John Jeremiah Bigsby, M.D.,  the first to promote what we now call stromatolites as evidence of life in the Precambrian?

 

John Jeremiah Bigsby, M.D.(1792-1881) – Geologist, Physician, Entomologist, Author and Artist– is no stranger to those with an interest in the geology of Canada.  Before Sir William Logan and before Elkanah Billings arrived on the scene, John Jeremiah Bigsby was considered the person most knowledgeable on the subjects of geology and paleontology in the two Canadas. In the years 1820 -1826 he was the medical officer attached to the British party settling the boundary between the United States and British North America, and studied the land surrounding Lake Huron and Lake Superior.    While Bigsby reported on the geology at the outlet of the Kaministiquia River into Lake Superior  I’ve not been able to find that he reported concretions near Thunder Bay or that he reported  on the geology along the Kaministiquia .   This may have been because during the summer or 1823 the Americans were instructed to go out from Fort William and up the Kaministiquia River to Lake of the Woods, while the British party  (including Bigsby) took  the Pigeon River- Grand Portage route from Fort William.  (See Epic Wanderer: David Thompson and the Mapping of the Canadian West,  By D'Arcy Jenish, 2009, Bison Books, at page 228) 

However, Bigsby may have been one of the first to promote what we now call stromatolites as evidence of life in the Precambrian, when he reported on an interesting structure in metamorphic rocks of what we now call the Grenville Province, Canadian Shield.   In an article published in 1864 Bigsby reported that he had found on the North shore of the St. Lawrence, at the base of Cape Tourment, 36-40 miles below Quebec City, in close-grained quartzose gneiss,  “a circular, cup-like, organic (?) body, two or three inches in diameter, with much the look, as well as the size, of a Maclurea [a large gastropod], not, however, with gyrations, but with concentric rings, one within another; the summits are rounded and not sharp-ridged; no radiating striae nor reticulations were observed in it, but they may exist.   It might be very loosely compared to Spongarium interlineatum, or to a Chaetetes  ... It is probably organic; and Sir W. Logan intends to examine the locality carefully.  Near this fossil (?)  And for some hundred yards around, the gneiss....”   Unfortunately, I’ve found no further reference to this structure.   

Bigsby, J. J., 1864, On the Laurentian Formation, Part II, The Geological Magazine, Volume 1, pages 200 -206 at page 205    http://www.biodiversitylibrary.org/item/97056#page/238/mode/1up

The main thrust of Bigsby’s article on the Laurentian Formation is that because there is evidence of carbon, phosphorus, lime etc. in Precambrian rocks there should be  evidence of life, noting for carbon that “This substance is indispensable to organic structure, and is in very great quantity in the Canadas, almost always near to, or imbedded in, marble, which is often at the same time high in phosphate of lime, and contiguous to deposits of magnetic oxide of iron.  ... Four of the principal constituents of life are thus brought together in the Laurentian Group; and with every probability that they have been employed as such.”   His article has been largely ignored.

James Richardson’s 1872 Report of Spheroidal Masses and a Structure Resembling Coral

In the 1870 field season Mr. James Richardson of the Geological Survey of Canada explored the country north of Lake St. John, Quebec and described the geology from Lake Abatagomaw to Lake Wakinitchie, including near Lake Chibougamau.  Today we would call the rocks that Mr. James Richardson examined the Superior Province of the Canadian Shield.    Near a bay at the north end of Lake Abatagomaw he mentioned “there are considerable exposures of flattened spheroidal or reniform masses, from a few inches to upwards of a foot in diameter.   They are made up of an indurated greenish and purplish argillaceous rock, which is jaspery in its texture. When sections of these spheroids have been exposed to the weather, they present a concentric arrangement of various shades of colour, becoming lighter towards the center.”   Past Lake Chibougamau Mr. Richardson  reported on “a blackish limestone, about a foot thick, interstratified with serpentine.  Dr.  Hunt, while examining these rocks, had a portion of the limestone sliced for examination under the microscope, which revealed a structure resembling that of some coral....This Mr. Billings thinks, is a coral, but not determinable generically.” 

Richardson, James, 1872, Report on the Country North of Lake St. John, in Geological Survey of Canada, Report of Progress, 1870-1871 at pages 292 and 293

In the 1884 field season A. P. Low of the Geological Survey of Canada examined the rocks near Lake Chibougamau that has been examined by Mr. Richardson and the rocks around Lakes Mistassini and Mistassinis.  He reported:   “The lower beds resting unconformably on the gneiss, at the western end of Lake Mistassini,  are made up of a dark bluish-grey limestone, holding concretionary masses of dark blue chert, with thin bands of black argillaceous shale.  Above this are thin beds of light blue fine-grained dolomitic limestone, weathering yellow, interbedded with thin layers of a gritty limestone, containing large quantities of sand.   ....  Although closely examined, none of the above beds gave any evidence of fossil remains, the supposed fossils found by Mr. Richardson having, on closer examination, proved to be only mineral concretions.”

Low A. P., 1885,  Report of the Mistassini expedition, 1884-5, Geological and Natural History Survey of Canada, Annual Report, Volume 1, (1885),  Part D, at page 32D

Over a century after Mr. Richardson’s report,  H.J. Hofmann commented:   “Stromatolites were first reported from the Lake Mistassini area of Central Quebec more than a hundred years ago (Richardson 1872) and most subsequent geological reports make mention of them....   Illustrations accompanying a few of these reports show stratiform, nodular, domal and short columnar types...”

Hofmann H. J., 1978,  New stromatolites from the Aphebian Mistassini Group, Quebec; Canadian Journal of Earth Sciences, v. 15, no 4, 571-585, at page 571.
www.nrcresearchpress.com/doi/abs/10.1139/e78-062

Calcareous Bunches, Keratose Sponge and Snow-shoe Tracks at Vermilion Lake near Sudbury, and Similar Rocks in Minnesota that Remind one of Cryptozoon

 

During the summer of 1889  the Toronto meeting of the Geological Association of America afforded Professor N. H. Winchell, state geologist for Minnesota,  the opportunity to look at the rocks of Northern Ontario with Dr. Bell and Dr. Selwyn of the Geological Survey of Canada.   At Vermilion Lake, at the crossing of the Vermilion river, about 30 km west of Sudbury, Winchell (1889) reported of a fine grained black slate that “In it are some curious calcareous bunches, or “concretions”, which recall the soft masses in which Dr. T. Sterry Hunt reported evidence of
keratose sponge, found near Thompson, Minnesota.  Some of these masses are two feet in diameter, with rounded outlines, presenting on the weathered or glaciated natural surface a striking contrast with the rock that encloses them.  They are locally designated “snow-shoe tracks”.”   While true concretions have been reported from the Chelmsford Formation along Highway 144 about 4 kilometers north of Vermilion Lake, I believe that Winchell’s concretions/snow-shoe tracks are stromatolites from the Onwatin Formation or Vermilion Formation, in part because of his comments below. 

Winchell, N. H., 1889, Further Observations on the Typical Huronian, and on the Rocks About Sudbury, Ontario, in Report for 1889, Eighteenth Annual Report, Geological and Natural History Society of Minnesota, at page 54

In 1890 field season Dr. Winchell reported his examination of slates near Northern Pacific Junction, Minnesota and reported finding structures similar to those that he had observed at  Vermilion Lake near Sudbury.  This time he remarked on the prevalence of the “dark calcareous lumps or secretions.   These are the same that Drs. Hunt and Dawson supposed to contain traces of a keratose sponge, and which Dr. Selwyn pointed out as “snow-shoe tracks” – so called by the Indians– where their weathered contour- appear on the slates of the Vermilon River. ... When these lumps are fresh they are gray, crystalline apparently consisting essentially of lime, in which, in some parts, the small crystals of calcite are visible in compacted marmorized structure.   But there is a layered, concentric, rather coarse structure reminding one of Cryptozoon, across which perpendiculary there is a transverse jointage...”.

Winchell, N. H., 1893, Field Notes of N. H. Winchell, in Report for the year 1891, Twentieth Annual Report, Geological and Natural History Society of Minnesota, at page 29-30.

Arthur Harvey – Animikie Cannon balls and Pelotechthen Balanoides

 

In April, 1889 Arthur Harvey delivered a paper before The Canadian Institute on the geology northwest of Lake Superior in which he mentioned that the rocks in the Lake Superior country “seem to contain no fossils, unless the “cannon balls” of the Animikie slates be such.”   He did note that “the presence of particles of graphite and phosphate and the collection of iron into enormous beds seem to lead to the belief that the epoch of their formation was not anterior to the existence of life upon the world.”

Harvey, Arthur, 1889, Broad Outlines of the Geology of the Northwest of Lake Superior, Proceedings of the Canadian Institute, Third Series, Volume VI, 218-225 at 235

In November, 1889 Arthur Harvey delivered a paper before The Canadian Institute in which  he mentions the Animikie formation’s locally called  “cannon-balls”, which he named “Pelotechthen Balanoides– an acorn-shaped thing, grown in or from mud.”   He commented “The uniformity of shape proves these things to be a growth; they are sometimes like an orange, often ovoid, and they so often have a slight protuberance on the upper side that I compare them rather to acorn than to an orange or an egg.  Their internal structure, too, proves them a growth... [T]here is a very regular layer of pyrites around the nodule...   This pyritous ring I have never failed to notice....  I submit that no mere mineral nodule would attain the size of many of these spheroids.   I would have thought this growth a protospongia, except for the conditions under which it seems to have lived, that is if it be a zoophyte. .... [T]hey are from the bigness of a hen’s egg to that of a coal scuttle.”

Harvey, Arthur, 1891, Pelotechthen Balanoides,  Transactions of the Canadian Institute, Volume 1, pages 213-215

I’ve found no reference where anyone else mentions Pelotechthen Balanoides.

PALEOZOIC ROCKS

Logans and Murray’s 1852 Reports on Concretions in the Paleozoic Rocks of Eastern Ontario

  In the 1851 field season W.E. Logan and Alexander Murray of the Geological Survey of Canada examined the Paleozoic rocks comprising the country lying between the Ottawa River and the St. Lawrence River, from the junction of the two rivers (just  west of Montreal) “to the neighborhood of Bytown on the one and Kingston on the other.”    They reported on numerous concretions–structures that we would now identify as stromatolites.  Here is part of Mr. Logan’s report on the Calciferous beds from Carillon to Grenville:

“Immediately beneath the two-feet bed of limestone there is a singular and extensively spread concretionary layer, in some exposures of which, surfaces of half an acre shew the concretions, consisting of concentric layers, cut in half and closely packed together, some of them being two to three feet in diameter.”

Logan, W. E., 1852, Geological Survey of Canada, Report of Progress for the Year 1851-52, at page 19. 

Here is part of Mr. Murray’s report:

“At Battle Windmill, a little over a mile below Prescott, the following descending section was measured:--
Pale grey arenaceous impure limestone, weathering bright yellow, and rapidly disintegrating on exposed surface; the bed is filled with concentric concretionary balls, the concentric layers of which are frequently interlined with white calc-spar... 1 ft, 2 inches”

Alexander Murray, 1852, Report of Andrew Murray,  Assistant Provincial Geologist, Addressed to W. E. Logan, Provincial Geologist, in Logan, W. E., 1852, Geological Survey of Canada, Report of Progress for the Year 1851-52, pages 58 - 91,  at pages 67-68.

Both of those reports were repeated in Logan, W. E., 1863, Geology of Canada, Geological Survey of Canada, Report of Progress from its Commencement to 1863, 983 pages, in his discussion of the Calciferous Formation (in Lanark county, now the March and Oxford) and Chazy Formations.   When discussing the Calciferous, Logan mentions (at pages 112-113)  that “On this part of the Ottawa [River at Rigaud] the middle portion of the formation is concealed; but the summit is met with on the bank of the river above Carillon, where about a hundred feet of arenaceous limestone and bituminous calcareous clay-stone terminate in a singular and extensively spread concretionary layer, like that noticed in the section below Prescott. In some of the exposures of it on the Grenville canal, about a mile below Grenville village, surfaces of half an acre shew the concretions, consisting of concentric layers seemingly cut horizontally in half and packed closely together, some of them being two to three feet in diameter.”

 When discussing the Chazy formation Logan mentions (at page 134) “ Yellowish-grey concretionary limestone, weathering yellowish-brown; the concretionary masses are from six to 18 inches in diameter, and the concentric layers of the concretions thin” and (at page 174) “Black shale supplied in abundance with a coral, of which the specimens have been lost; the upper part holds large concentric concretionary nodules of fine grained black limestone, passing in parts into a bed of black limestone eight inches thick.”

Bernstein   (1992) provides the most easily understood analysis of Logan’s Calciferous formation (breaking it into Theresa, a middle Beauharnois, and an upper Carillon), and  includes a schematic cross-section, Figure 2, entitled “Generalized lithostratigraphy of the Beekmantown Group in the St. Lawrence Lowlands, Quebec and Ontario” showing the location of domal and columnar stromatolites in the various formations.  He also includes a  photograph with the caption “Geologist stands on exhumed, large domal stromatolites similar to those described by Logan (1852, 1863) and referred to as Cryptozoon by Grabau (1936).”

Bernstien, L, 1992,  A revised lithostratigraphy of the Lower-Middle Ordovician Beekmantown Group, St. Lawrence Lowlands, Quebec and Ontario, Canadian Journal of Earth Sciences 29, 2677-2694 (1992)

Wilson and Wilson - Cryptozoon and Concretions in the Oxford Formation of Eastern Ontario

 

In earlier blog postings I  mentioned the following two publications of the Geological Survey of Canada:

Wilson, Morley E., 1924, Arnprior-Quyon and Maniwaki Areas, Ontario and Quebec, Geological Survey of Canada, Memoir 136, 152 pages.  

Wilson, Alice E., 1946, Geology of the Ottawa-St. Lawrence Lowland, Ontario and Quebec,
Geological Survey of Canada, Memoir 241, 66 pages.  

Both publications provide photographs of what we now call stromatolites.    Interestingly,  while Dr. Morley Wilson wrote the earlier paper, he was the one more willing to consider the structures as being algal growths.   Dr. Alice E. Wilson was in doubt as to whether the structures were concretions or algal growths.

Below is Dr. Morley Wilson’s a photograph of outcrop of Beekmantown dolomite exhibiting  Cryptozoon, lot 21, Concession X, Fitzroy Township, Carleton County, Ontario – his plate VIII.

That  photograph was taken in 1917 by Dr. Morley Wilson when he conducted   field work in the Arnprior-Quyon area.  Dr. Morley Wilson commented (at page 45) that “Most of the typical Cryptozoon are a few inches to 18 inches in diameter, but in places somewhat similar, flat, concentrically domed masses are present  that attain a diameter of several feet.   As seen in horizontal cross-section on the surface of an outcrop the Cryptozoon are circular in form (Plate VIII), but where they are exposed in vertical section they are generally considered flattened and dome-shaped.”

Below is photograph 81893 that Dr. Alice E. Wilson included in Memoir 241 published in 1946.

The caption to the photo, which is Plate II B, is “Oxford dolomite containing crytozoons and showing the characteristic weathering along joint planes.”   In the text of the memoir Dr. Alice E. Wilson names the Beekmantown dolomite as the Oxford formation “after Oxford township, Grenville county, Ontario, where it is widely exposed.”  She also mentions that “Many of the dolomitic beds contain hard spherical masses, from six inches to 2 feet in diameter, that weather concentrically (Plate II B).  They have been considered variously as concretions or as algal growths called ‘cryptozoons’.    Natural Resources Canada provides an online searchable database of photographs taken by field officers of the Geological Survey of Canada.  In the database Photo Number   81893 has the  Caption “Lot 15, Con. viii, Osgoode Twp. Ont. Concretionary Structures In Beekmantown Dolomite”, and mentions that the Photographer is “Wilson, A. E.” and that the photo is dated  1936.

Cryptozoon Structures in the Nepean Sandstone/Potsdam Sandstone

In my November 4,  2015 blog posting I mentioned that in 1924 Dr. Morley E. Wilson of the Geological Survey of Canada had reported that an outcrop of Nepean Sandstone northwest of Ottawa “exhibits concentric ridge forms up to 8 inches in diameter, somewhat similar in appearance to the Cryptozoon structure seen in the Beekmantown dolomite farther to the eastward.”   I also mentioned that within the last two decades numerous authors have reported stromatolites in the Potsdam Group sandstone (the upper formation of which is the Nepean). 


There were many early reports of concretions in the Potsdam sandstone.   Many are associated with the cylindrical structures that are considered to be dewatering structures resulting from springs.   The concretions associated with the cylindrical dewatering structures (e.g., those reported at Rossie, New York  by  Franklin Hough (1853), or those that Dr. Selwyn looked at near Kingston –see Anglin, Boyle and James (1888))  could easily have formed by water circulating from the dewatering structures.    However, there are many other early reports of concretions in the Potsdam from Ontario and New York State.   For example, Logan (1863) mentions (at page 92) a two foot layer of “Blood-red coarse sandstone with concretionary nodules” near Charleston village.   I suspect that some of the early reports of concretions could be stromatolites.

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I found it interesting to look back to see how stromatolites were first identified by early geologists and to see how many different common names were used before the term stromatolite was settled on.   I have not mentioned all of the names that my research uncovered, as I’ve restricted this posting to localities in Canada or in the Canadian Shield.   I have also not covered the proliferation of scientific names that erupted following Hall naming Cryptozoon in 1883.

Christopher Brett
Perth, Ontario  

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1.  In 1847 Logan and Murray spelt the river’s name as Kamanitiquia; in 1863, Logan spelt it as Kaministiquia.  Bell spelt it Kaminitiquia.  It is now spelt Kaministiquia.   Murray,  Logan and Bell refer to the falls on the Kaministiquia River as the Grand Falls.  It is now called the Kakabeka Falls.  Bell’s Lake Ka-zee-zee-kitchi-wa-ga-mog is now the pedestrian Loch Lomond.  I have not been able to determine the current name for Sucker Brook.

2.  Photographs of stromatolites in the Thunder Bay area can be found on the following web pages:

http://www.jon-nelson.com/stromatolites-in-thunder-bay-area#more-344

http://www.mindat.org/sitegallery.php?loc=222478

http://www.mindat.org/sitegallery.php?loc=222731

https://www.geocaching.com/geocache/GC31G74_kakabekia-a-living-fossil

Fluvio-glacial Sculpted Forms in Outcrops Near Newboro, Eastern Ontario

Geologists and geographers who study glacial eroded features in bedrock can distinguish between: (a) features  which are formed by boulders, gravel and sand  trapped under the glacial ice that abrade the bedrock as the glacier pushes and pulls the boulders,  gravel and sand along; and (b) grooves and sculpted forms that have been cut into the bedrock by sediment laden, subglacial, meltwater flow.    Glacial striae and chatter marks are examples of the former, while cavettos, potholes, spindles, v-shaped grooves, Sichelwannen, and Muschelbrüche are examples of the latter.  

Below are photographs that I took of outcrops of sandstone a few kilometers east of Newboro, Eastern Ontario along the north side of County Road 42.  The first three photos show spindle flutes and possibly Cavettos cut into the bedrock.   Also of interest is the sharp rim (or  ridge) at the top of the outcrop that is visible in the third photo.  The fourth photo shows potholes or troughs. 

I believe that these eroded features were caused by sediment laden, subglacial, meltwater flow, rather than by abrasion caused by boulders, gravel and sand trapped under and carried along by the glacier.

Below I’ve provided a number of articles that are worth a look if you are interested in meltwater eroded sculpted forms.

Christopher Brett
Perth, Ontario

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John  Shaw,  1988 
Subglacial erosional marks, Wilton Creek, Ontario
Canadian Journal of Earth Sciences, 1988, 25(8): 1256-1267
http://www.nrcresearchpress.com/doi/pdf/10.1139/e88-121

David R. Sharpe and John Shaw, 1989
Erosion of Bedrock by subglacial meltwater, Cantley, Quebec;
Geological Society of America Bulletin, Volume 101, p. 1011-1020
http://mysite.science.uottawa.ca/idclark/quat2333/labs/cantley/cantley_sharpe.pdf

Philip S.G. Kor,  David R. Sharpe and John Shaw, 1991   
Erosion of bedrock by subglacial meltwater, Georgian Bay, Ontario: a regional view;
Canadian Journal of Earth Sciences, volume  28, 623-642. DOI: 10.1139/e91-054
http://www.nrcresearchpress.com/doi/pdf/10.1139/e91-054

John Shaw, 1994
Stop 6: Large-scale bedrock fluting, Elginburg; Stop 7: Meltwater erosional marks, Wilton Creek (Thorpe Pit); Stop 12: Meltwater erosional marks, Marysville; in A field guide to the glacial and postglacial landscape of southeastern Ontario and part of Quebec,  Robert Gilbert, compiler, 1994
Geological Survey of Canada Bulletin 453, 80 pages; doi:10.4095/194483
http://geoscan.nrcan.gc.ca/starweb/geoscan/servlet.starweb?path=geoscan/fulle.web&search1=R=194483

Philip S.G. Kor and Daryl W. Cowell, 1998
Evidence for catastrophic subglacial meltwater sheetflood events on the Bruce Peninsula, Ontario
Canadian Journal of Earth Sciences, 35(10): 1180-1202, 10.1139/e98-067
http://www.nrcresearchpress.com/doi/abs/10.1139/e98-067#.VqFFyk9c9K0

Mandy J. Munro-Stasiuk,  Timothy G. Fisher and , Christopher R. Nitzsche, 2005
The origin of the western Lake Erie grooves, Ohio: implications for reconstructing the subglacial hydrology of the Great Lakes sector of the Laurentide Ice Sheet; Quaternary Geology Reviews, vol. 24, 2392-2409 
http://www.eeescience.utoledo.edu/Faculty/fisher/Fisher/Publications_files/MunroStasiuk_etal_QSR05.pdf

More Evidence of Microbial Mats in Potsdam Sandstone near Newboro, Eastern Ontario

Winter has arrived in Eastern Ontario.  Eight centimeters of snow fell last night and more is forecast for today.   I’m glad that on December 26th I took the opportunity offered by the absence of snow  to revisit the area around Newboro and to look at outcrops near Westport.  I’d wanted to check for glacial meltwater eroded outcrops (and found some) and wanted to look again for further evidence of microbial mats.  Below I report on three outcrops  near Newboro.   The first two outcrops are mapped as Potsdam Group sandstone.  All of the outcrops are about  four kilometers south of the Rideau Lakes Fault. 

The silver ruler in the following photographs is one meter (39 inches long).  The blue ruler is 12 inches (30 cm) long.

First: An Outcrop Revisited

This is one of the outcrops from my last blog posting, the one mentioned under the subheading
‘Biofilm Structures’ where I provided  two photographs showing  a bedding parallel view of distorted laminations in quartz sandstone.    Below are photographs of additional distorted sandstone laminations visible at this outcrop.  The structures are difficult to envisage in sandstone unless the beds were bound by microbial mats.   The first photograph  may show a mat roll up structure.

Second:  Distorted Layers in Flat Lying Beds of Potsdam Sandstone

Below are photographs showing a distorted bed that is up to about 12 inches (30 cm) thick contained  within a sequence of flat lying beds of sandstone.

This distorted bed contains broken,  folded and crinkled layers, plus layers that appear to have been thrust over or under other layers.    I believe that this distorted bed represents pre-lithification  distortion of  biomats and stromatolitic layers in the sandstone, probably caused by seismic activity along the Rideau Lakes Fault.    Seismic activity caused rupturing and folding of the unconsolidated sediment, but the biofilms preserved the laminations in the strata. 

The mechanism that I have proposed to account for the  30 cm wide distorted bed near Newboro is analogous to the model proposed by Donaldson and Chiarenzelli (2004) to account  for the meter thick convoluted layer in the Nepean sandstone outcrops in Kanata, Ontario, photographs of which were included in my  November 4,  2015 blog posting.    Both outcrops display soft-sediment deformation   in  sandstone, where seismic activity is the likely cause of the deformation.  
   

Third:  A Badly Weathered Outcrop

I’ve included this outcrop because it has weathered in such a manner that it looks like the outcrop in Kanata, in a field off the Old Quarry Trail, photographs of which were included in my  November 4,  2015 blog posting.   It is missing the convoluted folds shown at the outcrop in Kanata, but otherwise the pattern of weathering is the same.  Both the outcrop in Kanata and this outcrop show repetitive, weathered out, thin layers in sandstone.   Below are photographs of the side view and the top view of the outcrop near Newboro.

I did not have my rock pick or sledgehammer with me on the 26th, but pulled a piece off the third outcrop, took it home, and cracked it with a small sledge.  It’s sandstone, badly weathered sandstone, but sandstone.

Christopher Brett
Perth, Ontario
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Addendum (January 5, 2016):         

In the comment below Howard Allen of Calgary has suggested that the second outcrop may represent evaporite accumulation, subsequent solution and collapse.  Others have reported on evaporites in Potsdam sandstone, and have suggested that they are responsible for observed structures in the sandstone. 

Wolf and Dalrymple (1984) mention that “At one locality near Phillipsville, a zone of disrupted laminae caps the burrowed beds.  The nature of the laminae suggests collapse into small cavities. .... The disrupted laminae which cap the cycle at the Phillipsville locality may represent the collapse of overlying sand into cavities formed by the dissolution of evaporites, such as gypsum or halite (B.W. Selleck, Colgate University, personal communication, 1983).” 

Wolf and Dalrymple (1985) mention that “the tops of cycles are disrupted by soft-sediment deformation, due either to the leaching of evaporites or to (earthquake induced?) liquifaction. ....Evaporite moulds in one outcrop of this facies near Gananoque... give evidence of elevated salinities, a finding that is compatible with an evaporite-solution origin of the soft-sediment deformation features.”

Donaldson and Hilowle (2002) report for an outcrop of quartz arenites of the Nepean Formation in Kanata that they observed “evaporite pseudomorphs, including silica-replaced rosettes of barite and/or gypsum” and “a distinctive unit of synsedimentary breccia inferred to have formed in response to dissolution of a layer of bedded evaporites”.

Donaldson and Chiarenzelli (2004) suggest,  for one of the outcrops of Potsdam sandstone (Nepean Formation)  at Kanata, that “a few beds that stand out as glassy markers display abrupt truncations (Figure 6), suggesting that they may have been penecontemporaneously cemented, and then locally disrupted by erosional undercutting of unconsolidated substrate, localized upwards pressure associated with dewatering, or dissolution of intercalated evaporites.”    

Sanford and Arnott (2010) reported that the  “Imperial Oil Ltd., Laggan No.1 borehole encountered numerous gypsum interbeds throughout the upper half of the Nepean Formation.”  In addition they noted that “Fairly extensive brecciation in the GSC Lebreton No.1 borehole, and to a lesser extent in the GSC Russell No.1 borehole, might also suggest the initial presence of minor halite in those areas, with subsequent dissolution and collapse.”  Further, “The widespread paucity of normal marine fossils, except for local occurrences of trace fossils, represents evidence of elevated salinity throughout the Ottawa embayment.   The occurrence of stromatolites, which can survive and even thrive in hypersaline conditions, is also a good indicator of evaporitic conditions.”

(Added: September 28, 2016)
David Lowe (2015, 2016), in his work on the Potsdam strata has recognized six siliciclastic paleoenvironments: (a) braided fluvial, (b) ephemeral fluvial, (c) aeolian erg, (d) coastal sabkha, (e) tide-dominated marine and (f) open-coast tidal flat.   Wikipedia mentions that “Sabkhas are supratidal, forming along arid coastlines and are characterized by evaporite-carbonate deposits with some siliciclastics. Sabkhas form subaerial, prograding and shoaling-upward sequences .”   The sabkha facies of the Potsdam Group are found in sandstone that  in Ontario we call the Nepean Formation, in Quebec they  call the Cairnside and in New York State they call the Keeseville.

Dewatering Structures, Biofilm Structures, Glacial Striae and Chatter Marks in Potsdam Sandstone near Newboro, Eastern Ontario

It has been a remarkably warm December for Eastern Ontario and we have yet to receive anything more than a light dusting of snow.  Yesterday, December 22nd, it was 8 degrees Celsius (46 degrees Fahrenheit), and  I couldn’t help but take the morning off work to do some Christmas shopping and to look at some outcrops. 

Below are photographs that I took yesterday of glacially polished  outcrops of Potsdam Sandstone a few kilometers north of Newboro, Ontario.    The sandstone has most recently been mapped as the Nepean Formation of the Potsdam Group by the Ontario Geological Survey and as the Covey Hill Formation of the Potsdam Group by the Geological Survey of Canada.

Dewatering Structures

The first three photographs show parts of three outcrops that are within about 270 feet (80 meters) of each other.  The first and the second photos show excellent examples of small dewatering structures.  The third photo is less convincing, but likely shows small dewatering structures.

     
In the second photo it is not clear what has weathered out of the surface layer to produce the pockmarked surface.   Many of the holes are rounded or peanut shaped.  One possible interpretation is that they represent gas bubbles trapped below a biomat.   Below are three more photographs of the pockmarked surface.   It appears that many of the bubbles have merged into chains or patches, resulting in  structure analogous to Kinneyia.

Biofilm Structures

The next two photographs provide a bedding parallel view of distorted laminations in quartz sandstone.  I believe the laminations to be biofilm structures in the quartz sandstone (rather than a distorted dewatering structure), where interlayered microbial mats provided cohesion during deformation.

It is possible that these distorted laminations are seismites.  The outcrops are about four kilometers south of the Rideau Lakes Fault and about the same distance from the soft-sediment deformation structures (seismites) mentioned in my October 22,  2015 blog posting.

Glacial Striae and Chatter Marks

Glacial striae and chatter marks were present on the surfaces of a number of the outcrops that I looked at.   In addition a few of the outcrops show prominent noses pointing in the same direction as the striae and chatter marks.   The next two photos provide examples of the glacial striae and chatter marks.

Possible Sandstone Dikes in Sandstone (or a Torn Microbial Mat)

Christopher Brett
Perth, Ontario       

Problematic Markings (Dubious Fossils) in Potsdam Sandstone

Below are two photographs that I took over two years ago of one side of a loose slab of Potsdam sandstone that I noticed at the quarry at Ellisville in Eastern Ontario.    The photographed side has a yellow coating that is probably Limonite.   All other sides of the slab are the pink and beige colours of the Covey Hill formation sandstone, Potsdam Group that is found in this quarry. 

Questions that have puzzled me for the last few years include: Are the raised forms fossils?  If the raised forms are fossils, are they body fossils or trace fossils?  and  If the raised forms aren’t fossils, how were they formed?   I’ve not found a convincing answer to any of those questions. My initial impression was that the raised forms were dubious fossils (markings possibly not of biogenic origin), and that is still how I would classify them.

Interestingly, I’ve found some photographs of somewhat similar problematic forms in two papers authored or co-authored by the late Dr. Hans Hofmann in rocks reported to be of Ediacaran age.  See:

Hofmann, H.J., 1988,  Synopsis of Precambrian Fossil Occurrences in North America, Chapter 4 in Geology of the Precambrian Superior and Grenville Provinces and  Precambrian Fossils in North America, (Co-ord.)  S. B. Lucas and M. R. St-Onge, Geological Survey of Canada, Geology of Canada, No. 7, p. 271-376, Plate 2E at pages 302-303.

Hofmann, H.J., Mountjoy, E.W. and Teitz, M.W., 1991
Ediacaran fossils and dubiofossils, Miette Group of Mount Fitzwilliam area, British Columbia; Canadian Journal of Earth Sciences, v. 28(10), p. 1541-1552, Plates 8C, 8D,  8E, 8F, 8J.
www.nrcresearchpress.com/doi/abs/10.1139/e91-138

Below I’ve provided Plate 2E from Hofmann (1988) which was originally plate 8F in Hofmann, Mountjoy and Teitz (1991).   The scale bar is 1 cm.

Below I’ve  provided Plates 8C, 8D,  8E and 8J from  Hofmann, Mountjoy and Teitz (1991).

Copyright in the photographs shown in the Plates belongs to National Research Council of Canada and Canadian Science Publishing. They  are reproduced under license from NRC Research Press.

Hofmann, Mountjoy and Teitz (1991) found and reported on a number of disc and elliptical shaped fossils (including Charnodiscus and Nimbia) that are worth reading their article to look at (but don’t resemble anything that I found), a vermiform structure that they equated with Zolotytsia, and seven types of dubiofossils which they classified alphabetically under the headings from Dubiofossil A to Dubiofossil G.

Hofmann, Mountjoy and Teitz (1991)  describe plate 8F as showing “Two partly overlapping vermiform markings.... The two specimens juxtaposed in such a way as to give the impression of being wound around each other ... or lying contiguous side-by-side for at least half their lengths.”   They  mention that “The markings appear to [be] those of some limp, soft-bodied cylindrical organism, or part of an organism, rather than a trace fossil. ... Structures of comparable physical consistency appear to be the much more regular spiraliform fossil Zolotytsia of Fedonkin (1985) and the Cylindrichnus of Glaessner (1969).

Plates 8C and 8D show two specimens which were discussed under the heading Dubiofossil C and were described as a tapering  “rectilinear frond-like structure” with rounded end, which they noted “resemble an unnamed frond-like impression from the Ediacaran... [and] also are like the proximal portions of the stems of Charnodiscus oppositus ... and may represent the stalk of similar organisms.” 

Plates 8E and 8J they assigned to Dubiofossil D and described as a “Cleavage reliefs of short, undulating furrow and corresponding ridges,... some portions having pinch-and-swell appearance.  Cross sections indistinctly round.”  They remarked that  the specimens “may be burrows comparable to Phanolites or Torrowangea.”
   
I’m not prepared to speculate as to whether the raised markings on the slab that I photographed could be body fossils or trace fossils, and if they are such, what they resemble.  All I can say is that the markings on the slab that I photographed are somewhat similar to and as problematic as the dubiofossils identified by Hofmann, Mountjoy and Teitz (1991). 

Second Specimen

Below are photographs of a loose specimen of Potsdam sandstone that I collected over about two years ago in Burgess Ward of Tay Valley Township, Lanark County from a waste pile resulting from the digging of drainage ditch along Stanley Road.   Both Nepean sandstone and Covey Hill sandstone of the Potsdam Group have been mapped in this area.  I believe the specimen to be Nepean sandstone as numerous other specimens from the same drainage ditch display U-shaped burrows. 

The circular, elliptical and spheroidal markings, which are composed of the same sandstone as the host, are problematic.   Are they concretions? Trace fossils? 

Christopher Brett
Perth, Ontario

In 1924 a report of Stromatolites in Nepean Sandstone by Dr. Morley E. Wilson of the Geological Survey of Canada, and Other Reports of Stromatolites and Biofilms in the Potsdam

At the end of this blog posting I’ve provided a list of articles discussing stromatolites and biofilm structures in Potsdam (Group) Sandstone.   Almost all of the articles will be known to those who have  worked on the Potsdam or who have written about stromatolites or  biofilms in siliclastic sediments.  There are two references that will catch people by surprise, the first of which is  Dr. Morley E. Wilson’s publication from 1924:

Wilson, M.E., 1924,
Arnprior-Quyon and Maniwaki Areas, Ontario and Quebec, Geological Survey of Canada, Memoir 136, 163 pages.

Dr. Wilson’s article is worth reading if you are interested in stromatolites, as he reports on stromatolites found in three different formations:  Nepean sandstone, Beekmantown Dolomite (now Oxford Formation dolostone) , and the Chazy/Aylmer Limestone (now St. Martin Member of Rockcliffe Formation).   More importantly, Dr. Wilson’s report  has been overlooked as being the first to report on stromatolites in Phanerozoic quartz sandstones.   In this publication  Dr. Wilson  mentions that in the Arnprior-Quyon map area  he found two small outcrops of “exceedingly fine grained, white, granular”  Nepean sandstone with a maximum thickness of two feet.  One of these outcrops, a small outcrop of Nepean sandstone on the roadside at the south end of lot 20, concession VIII in Fitzroy township, Ontario, is important because in places the weathered surface of the sandstone  “exhibits concentric ridge forms up to 8 inches in diameter, somewhat similar in appearance to the Cryptozoon structure seen in the Beekmantown dolomite farther to the eastward.”   I believe that Dr. Morley Wilson’s report is significant because it is generally accepted that a 1968 article by Richard A. Davis was the first to report on quartz sandstone stromatolites in Phanerozoic rocks.    Dr. Wilson deserves the credit as Memoir 136 was published forty-four years prior to Davis’ paper.   

A little over a week ago I drove to Fitzroy township in an attempt to find Dr. Wilson’s  outcrop of Nepean sandstone on the roadside at the south end of lot 20, concession VIII in Fitzroy township.   Regrettably, I could not find an outcrop of sandstone.   I did find a very small outcrop of marble along the roadside.   A geological map accompanied Dr. Wilson’s memoir.  He did not identify Nepean sandstone in the legend to the geological map, mainly, I believe, because he found only two small outcrops of Nepean sandstone in the map area, and the outcrops were too small to map.    On his map he shows an outcrop along the roadside at the south end of lot 20, Concession VIII. The outcrop is oval to peanut shaped, and composed of marble.   As noted above, I found only a very small outcrop of marble.   I noted that the road along the south side of lot 20 is built up above the level of the surrounding ground.    In addition, a house, barn and a number of structures are on one side of the road where Dr. Wilson  mapped his outcrop.   I suspect that the outcrop was to a large part destroyed in the grading of the road and the construction of the buildings.

Dr. Wilson’s map shows additional outcrops of marble along the road that runs along the south side of Concession VIII.   I looked at a large outcrop at the south end of lot 18, but found no sandstone on top of the outcrop.

While  Dr. Wilson does not include a photograph of either of the sandstone outcrops in Memoir 136, he does include  photographs of outcrops of Beekmantown dolomite exhibiting  Cryptozoon and photographs of other outcrops.   Natural Resources Canada provides an online searchable database of photographs taken by field officers of the Geological Survey of Canada.   That database contains a number of photographs taken in 1917 by M.E. Wilson when he conducted the field work of the Arnprior-Quyon area,  including photographs that found their way into Memoir 136, but does not contain a photograph of the sandstone outcrop of interest.

In 1982 the Ontario Geological Survey re-mapped Fitzroy Township.  See:

Williams, D.A., Wolf, R.R.  and Rae, A.M., 1982,
Paleozoic Geology of the Arnprior- Quyon Area, Southern Ontario;  Ontario Geological Survey, Map P2726, Geological Series -Preliminary Map. Scale 1:50,000.  Geology 1982
http://www.geologyontario.mndmf.gov.on.ca/mndmfiles/pub/data/imaging/P2726/P2726.pdf

Williams, Wolf  and Rae’s map does not show an outcrop of Nepean Formation sandstone on lot 20, Concession VIII of Fitzroy Township.  They do show a small  outcrop of Nepean Formation sandstone fifteen kilometers southeast of Lot 20, Concession VIII at the corner of Kinburn Side Road and Limestone Road.   I examined that outcrop, but it does not exhibit Stromatolites or biofilms.

Sir William  ‘Eozoön canadense’ Dawson (1879) - A report of Stromatopora in the Potsdam Sandstone

I believe that Sir William Dawson also noted stromatolites or biofilm structures in Potsdam sandstone, but that he misidentified the specimen as Stromatapora when he mentioned the specimen in the following article:

Dawson, J. W., 1879
On the Microscopic Structure of Stromatoporidae, and on Palaeozoic Fossils mineralized with Silicates, in illustration of Eozoon (Read June 5, 1878); The Quarterly Journal of the Geological Society of London, Volume 35,  pages 48 - 67, plus Plates III and  IV, at pages 51 and 57
http://www.biodiversitylibrary.org/item/86266#page/5/mode/1up

In that article, when discussing occurrences of Stromatopora, Dawson mentions that: 

“They occur also in the Lower Silurian, though less abundantly; and the oldest specimen that I have seen is in the Potsdam Sandstone; and this, its structure not being preserved, may have belonged to Eozoon  rather than to Stromatopora.  The Lower Silurian species have usually very thin and continuous walls.” 

When reading that extract from Dawson’ paper it is important to keep in mind that when he is referring to the “Lower Silurian” he is referring what we now call the Cambrian and Ordovician. The Ordovician  was defined by Charles Lapworth in 1879, the same year Dawson’s paper was published.

Later in the same article Dawson provides a chart giving the geological distribution of the American Stomatoporidae and lists Stromatopora, sp., in the Potsdam formation.
   
I believe that Dawson’s references to Stromatopora in the Potsdam formation are actually  references to stromatolites or biofilm structures in the Potsdam, mainly because (A)  I believe that it would be very easy to mistake a poorly preserved specimen of a stromatolite for Stromatopora (and vice versa), (B) others have found stromatolites and biofilms in Potsdam Sandstones, (C) I have found no reference to anyone else finding  Stromatopora in the Potsdam sandstone, and (D) while the Potsdam sandstones are considered to be Cambrian, Stromatoporidae appear to have existed from the Ordovician to the Devonian.  Unfortunately, Dawson does not provide the location of the specimen from the Potsdam.

In fairness to Sir William Dawson, his paper from 1879 was published four years before James Hall (1883) provided the original description for Cryptozoön proliferum (the first named and scientifically described stromatolite).  In addition, others including S.A. Miller (1889) have noted that Cryptozoon resembles Stromatopora.  Further, I have found references which have acknowledged that certain structures were described as stromatopora before Hall gave them the name Cryptozoon.   (For example, William Alden (1918), when describing laminated, elliptical, domal structures – that we now call stromatolites – in the Medotta limestones of Wisconsin stated “They resemble certain structures which have been described as stromatoporoid growths , but to which Hall has given the name Cryptozoon....).    Dawson cannot be faulted for identifying a structure as stromatopora, when the first stromatolite had not been described when he wrote his paper.

Interestingly, eighteen years later Dawson (1896-97) corrected Walcott’s identification of Precambrian structures found in the Grand Canyon from stromatopora  to Cryptozoon, and corrected other earlier identifications of stromatopora to Cryptozoon, but did not go back to look at his own identification of stromatopora from the Potsdam sandstone.

Outcrops of Biofilms and Stromatolites in the Nepean Formation Sandstone at Kanata

   
We are blessed in Eastern Ontario with outcrops of seismically disturbed beds of stromatolites and biofilms in the Nepean formation quartz arenites.  In their field trip guide Donaldson & Chiarenzelli (2004) provide two stops in Kanata  where one can  look at seismically disturbed beds of stromatolites and biofilms in the Nepean formation.  The two stops are different outcrops of the same bed.  Their stop 7 is an outcrop that is beside the on-ramp to the Queensway  (Highway 417) from Terry Fox Drive if you want to head west on the Queensway (to Arnprior or to Perth).   (Please note that it is illegal to stop a car on the on-ramp to a 400 series highway unless it is an emergency.)    Their stop 8 is in a field off the Old Quarry Trail over National Capital Commission Greenbelt  and is much safer to access.   Detailed descriptions of the outcrops at the two stops  can be found in their 2004  paper and in  (a) Hilowle, Donaldson and Arnott (2000) and  (b) Donaldson and Chiarenzelli (2007).    Also worth reading are Donaldson and Hilowle (2002),  and Donaldson, Chiarenzelli and Aspler (2005).

Below are photographs that I took a little over a week ago of the outcrop at stop 8 along the Old Quarry Trail.

    


The blue ruler is 12 inches (30 centimeters) long.   The silver ruler is 1 meter (39 inches) long.


Donaldson and Chiarenzelli (2004) mention that the outcrop shows “Convolute folds in a 1-m thick unit below a thin unit of foundered ‘half-moons and bananas’ formed by disruption of an early cemented layer of stromatolites above still -unconsolidated sand” caused by seismic activity.

Below are directions to Stop 8 (amended from those in the field trip guide):
Exit the Queensway heading south on Eagleson Road.  Cross Robertson Road/Hazeldean Road.  Keep in the left hand lane and make a left hand turn at the first stop light into the parking lot marked with a blue P5 sign.  Park your car.  With your back to Eagleson Road you will see three trails.  Take the trail farthest to your right, the most southerly trail.   Walk along the trail for about 200 meters.  You will pass under some overhead electric power lines.  Continue walking along the trail for another 100 meters.  The outcrop is about 10 meters to your right through the grass.

Additional outcrops of the convoluted layer can be found along the Old Quarry Trail, which is a 3.1 km long official trail plus additional unofficial loops.   The convoluted layer is highlighted  in a brochure discussing the geology along that trail that was  published by the National Capital Commission in 2000 entitled “Old Quarry Trail, The Making of a Landscape”  that is available online at

http://www.ncc-ccn.gc.ca/sites/default/files/pubs/NCC-Old-Quarry-Trail-Brochure-2000.pdf

The brochure provides a cross-section showing the relationship of the convoluted layer to the underlying and overlying flat layers of sandstone, and directs one to outcrops showing ripple marks in the sandstone, worm burrows in sandstone, glacial striations, glacial erratics, dolomite outcrops and the old flagstone quarry in sandstone.  The brochure mentions that “Even geologists are puzzled by ... (how the) convoluted layer formed” and suggests that “Perhaps one layer of sand did not lose its moisture as fast as the layers above and below it.  Remaining plastic... this layer may have buckled up in response to a sudden shock – perhaps a distant earthquake.”

Hilowle, Donaldson and Arnott (2000) and  Donaldson and Hilowle (2002)’s identification of the convoluted layer as representing deformed biofilms and stromatolites, coupled with Donaldson and Chiarenzelli (2004 and 2007)’s suggestion  that seismic activity had caused deformation in a stromatolite unit in Nepean sandstone provides an answer to the puzzle posed in the NCC’s brochure.   Donaldson and  Chiarenzelli (2004) suggest that “to account for the random tilted arrangement of stromatolites” their model “requires early cementation of the stromatolite unit above a still-unlithified substrate of water charged sand.  As a result of a seismic disturbance, the rigid unit of laterally linked silica-cemented stromatolites snapped apart along the thin inter-stromatolite links, allowing the now-separated heads to rotate and founder in random directions into the overpressurized sand.”

The convoluted bed in the outcrops found along the Old Quarry Trail has puzzled geologists for over sixty years.   In 1956 Dr. Alice E. Wilson included the outcrops in her field trip guide to the Ottawa area.    When discussing the sandstone outcrops south of Eagleson’s Corners she mentioned:

“The sandstone is made up of great swirls, each with a hard quartzite centre.   The beds below are flat, and the beds above, across the field, are flat.  Explanations are in order.  Several have been suggested but none proved.  One possibility is a slump before consolidation, but why the almost uniform size of the quartzite centres, and the uniformity in the size of the swirls?  Another suggestion is that the unconsolidated sand has been pushed up by ice on the seafloor. The same objection holds for this theory, and the additional one that no other evidence has been found indicating ice at this time.”

Donaldson and Chiarenzelli (2004 and 2007)’s suggestion that seismic activity caused deformation in a stromatolite unit in Nepean sandstone appears more likely than Dr. Alice E. Wilson’s suggestions.    

Additional  Reports of Stromatolites in Potsdam (Group) Sandstone

                          
I have found the following additional references to stromatolites in the Potsdam (Group) sandstones:

Hofmann and  Chartier (2006) report on two occurrences in Cairnside formation (the Quebec equivalent of the Nepean formation) orthoquartzites in the Montreal area.  They found:

A) “stromatolite-like strain patterns” at Melocheville, Pointe-du-Buisson.   They include a photograph as figure 22B with the caption “Plan view of ‘stromatolite-like’ strain patterns,” and a map of Point Du Buisson as Figure 21 upon which the structures have been mapped, including a note of one “area of abundant swarms of stromatolite-like strain patterns.”   The map is said to be by “Hofmann, in Clark, 1963.”

B) a “Chaotic bed indicating pre-lithification deformation, possibly as microbially bound sand (microbiolite)” at a roadcut beside the highway 132 entrance to the tunnel below the St. Lawrence Seaway at the Beauharnois Locks.  A photograph of that feature appears as Figure 25 Y at page 38 of their report.  That photograph could easily have been taken at the outcrops in Kanata that are described above.

Donaldson & Chiarenzelli (2007) provide photographs of deformed stromatolites and biofilms, plus a photograph of an outcrop near Chippewa Bay, New York.  For their  Figure 8(b)-1 Primary Structures, they mention “(B) Low-amplitude, laterally-linked stromatolites from the Potsdam Sandstone, along Highway 12 just east of Chippewa Bay, New York State, approximately 85 km due south of Ottawa.  The host rock is a medium grained, quartz cemented, quartz arenite.”

Professor Bruce Selleck (2008) reported stromatolites in dolomitic beds in the lower cyclic unit of the Upper Potsdam Member (=Keeseville Member) in the Southern Lake Champlain Valley at Stop 1 near Lake George Village and in outcrops close to his  Stop 3off NYS Route 22 north of Dresden

Sanford and Arnott (2010) mention the outcrops in Kanata and also mention that stromatolites occur “in various areas of New York State, notably near Chappel Corners where numerous solitary stromatolites were observed at station N-66".   Chappel Corners is about 10 km northeast of Theresa,  5 km east of Redwood and 10 km South of Chippewa Bay.

The Société de Paléontologie du Québec provides on its web site a Paleo guide to the Melochville area (written by Mario Lacelle,  Pierre Groulx and Paul Racicot) that discusses the outcrop at Pointe-du-Buisson and mentions that “des structures d’origine stromatolitique ont également été rapportés par Hofmann (1972).”    See:
 http://www.paleospq.org/NewPaleospq/paleoguides.html

I have not yet been able to locate a copy of Hofmann (1972) or Clark (1963). 
   
Evidence of biofilms in the Potsdam Group sandstone has been provided in scores of articles too numerous to individually mention,   other than the following.

Brand and Rust (1977) on a stratigraphic log of the type section of the Nepean Formation near Ottawa show three horizons where they recorded rip-up clasts in sandstone.   These are likely preserved biofilm structures that correspond with those reported by Erickson (1993) who  found sub-cylindrical and sub-triangular structures in the Potsdam Sandstone near Malone, New York that he classified as dubiofossils.   Professor Mark Erickson concluded that “algal layers were likely responsible for the quality of preservation of these unusual specimens.”

Salad Hersi and Lavoie (2000) on a stratigraphic section of the Cairnside Formation sandstone (the Quebec equivalent of Ontario’s Nepean Formation sandstone, and New York State’s Keeseville sandstone), show “Breccia (soft sediment deformation)”  at a horizon in the lower Cairnside and mention in their report that “In the lower part of the unit at locality 1, there is a brecciated zone due to soft-sediment deformation. The breccia clasts are lithologically similar to the clean quartz arenite of the Cairnside sandstone.”   This is consistent with biomat structures preserved during a seismic event. 

Christopher Brett
Perth, Ontario

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References and A Selected Bibliography of Articles on Stromatolites and Biofilm Structures in Potsdam Group Sandstone

Alden, William , 1918
The Quaternary Geology of Southeastern Wisconsin, with a chapter on the Older Rock Formations; U.S. Geological Survey Professional Paper 106 at page 74

Anderson, K., Dobie, N. Donaldson, J.A., and Arnott, R.W.C., 2004
Complex cementation history of a laterally extensive section within the Cambro-Ordovician Nepean Formation, Ottawa;  Program with abstracts GAC, MAC, CGU-AGC, AMC, UCG : joint annual meeting, May 12-14, 2004, Brock University, St. Catherines
http://gac.esd.mun.ca/gac_2004/search_abs/sub_program.asp?sess=98&form=10&abs_no=395

Brand, Uwe and Rust, Brian R. 1977
The age and upper boundary of the Nepean Formation in its type section near Ottawa, Ontario;
Canadian Journal of Earth Sciences, Volume 14, pages 2002-2006.

Clark, T. H., 1963
Field Trip 10- Breccia localities.  In: T. H. Clark (editor) Guide Book. Geological Association of Canada, 16th Annual Meeting, Montreal, pp. 95-104

Davis, Richard A. 1968
Algal stromatolites composed of quartz sandstone; Journal of Sedimentary Research,  v. 38  no. 3 p. 953-955

Dawson, J. W., 1879
On the Microscopic Structure of Stromatoporidae, and on Palaeozoic Fossils mineralized with Silicates, in illustration of Eozoon; (Read  June 5, 1878); The Quarterly Journal of the Geological Society of London, Volume 35,  pages 48 - 67, plus Plates III and  IV, at pages 51 and 57
http://www.biodiversitylibrary.org/item/86266#page/5/mode/1up

Dawson, J. W., 1896-97
Note on Cryptozoon and other ancient fossils; Canadian Record of Science, volume 7, October 1896,  203-219

Donaldson, J. Allan  2009,
Geoheritage 2.  Examples of Geoeducation, Geoconservation and Georescue Projects in Ontario;
Geoscience Canada, Volume 36 Number 3 September 2009, pages 102-106

Donaldson, J. A., and Hilowle, M.A., 2002,
Organic mats, evaporite pseudomorphs and soft-sediment deformation in quartz arenites of the Cambro-Ordovician Nepean Formation; GAC–MAC, Saskatoon 2002, Program with Abstracts,
http://gac.esd.mun.ca/gac_2002/search_abs/sub_program.asp?sess=98&form=10&abs_no=73

Donaldson, J.A., Munro, I., and Hilowle, M.A., 2002,
Biofilm structures, trace fossils and stromatolites in Early Paleozoic quartz arenites and carbonates of the Ottawa region, Ontario:  Twelfth Canadian Paleontology Conference (CPC - 2002), 29-30 September,  Program and Abstracts, page 12.  

Donaldson, J. A., and Chiarenzelli, J. R., 2004,
Stromatolites and associated biogenic structures in Cambrian and Ordovician strata in and near Ottawa, Ontario: New York State Geological Association, 76th Annual Meeting, Fieldtrip Guidebook, SUNY, Potsdam, New York, Trip F-1,  p. 1–20.

Donaldson, J.A., and Chiarenzelli, J.R., 2007,
Disruption of Mats by Seismic Events, chapter 8(b) in Atlas of Microbial Mat Features Preserved within  the Siliciclastic Rock Record;  edited by Juergen Schieber, Pradip K. Bose, P.G. Eriksson, Santanu Banerjee, Subir Sarkar, Wladyslaw Altermann, Octavian Catunean;
Elsevier,  324 pages at p. 245-247

Donaldson, J.A., Chiarenzelli, J.R., and Aspler, L.B., 2005,
 Siliciclastic stromatolites and biofilm structures: Conditions for preservation:
GAC–MAC–CSPG–CSSS Halifax 2005, Abstracts, p. 45-46.

Erickson, J. Mark, 1993
A Preliminary Evaluation of Dubiofossils from the Potsdam Sandstone; New York State Geological Association, 65th Annual Meeting, Field Trip Guidebook, Trip A3; pages 121-130

Hagadorn, James W. and  Belt, Edward S., 2008
Stranded in Upstate New York: Cambrian Scyphomedusae from the
Potsdam Sandstone; PALAIOS, 2008, v. 23, p. 424–441
DOI: 10.2110 /palo .2006.p06-104r

Hall, James (1883)
Cryptozoön, n.g.; Cryptozoön proliferum, n.sp;  New York State Museum of Natural History, 36th Annual Report of the Trustees, plate VI and Explanation

Hilowle, M.A., Donaldson, J.A., Arnott, R.W.C., 2000,
Biofilm-mediated structures  in quartz arenites of the Cambro-Ordovician Nepean Formation.
GAC-MAC Program with Abstracts v. 25, GeoCanada2000 – The Millenium Geoscience Summit, Calgary, conference CD,  [www.ironleaf.com, abstract 868.] 

Hofmann, H J., 1972
Stratigraphy of the Montreal Area - Stratigraphie de la région de Montréal; International Geological Congress, 24th Session, Montreal  Guidebook for Field Excursion B-03: 1-32

Hofmann, Hans J. And Chartier, Michel D., 2006
Canadian Paleontology Conference Field Trip Guidebook No. 11, CPC 2006, Redpath Museum, McGill University, October 13-16, 2006

Miller, S.A.  (1889)
North American Geology and Paleontology; Western Methodist Book Concern, Cincinnati, Ohio, 793 pages

Salad Hersi, O. and Lavoie, D., 2000
Lithostratigraphic revision of the Upper Cambrian Cairnside Formation, upper Potsdam Group, southwestern Quebec; Geological Survey of Canada, Current Research 2000-D4, 8 pages

Sanford, B. V. and Arnott, R. W. C. , 2010,
Stratigraphic and structural framework of the Potsdam Group in eastern Ontario, western Quebec, and northern New York State; Geological Survey of Canada, Bulletin 597,

Selleck, Bruce , 2008
Stratigraphy, Sedimentology and Diagenesis of the Potsdam Formation, Southern Lake Champlain Valley, New York;  New York State Geological Association, 80th Annual Meeting, Fieldtrip Guidebook

Williams, D.A., Wolf, R.R.  and Rae, A.M., 1982,
Paleozoic Geology of the Arnprior- Quyon Area, Southern Ontario;  Ontario Geological Survey, Map P2726, Geological Series -Preliminary Map. Scale 1:50,000.  Geology 1982
http://www.geologyontario.mndmf.gov.on.ca/mndmfiles/pub/data/imaging/P2726/P2726.pdf

Wilson, Morley E., 1924,
Arnprior-Quyon and Maniwaki Areas, Ontario and Quebec, Geological Survey of Canada, Memoir 136, 163 pages.

Wilson, Alice E., 1956
A Guide to the Geology of the Ottawa District; Volume 70, The Canadian Field Naturalist, pages1-68, Plates I-V, Route Map of Excursions

I have not included the recent papers on Climactichnites and Protichnites that discuss the preservation of the trackways due to biofilms, as I’ve mentioned most of them in previous blog postings and they are well known.