Tuesday, 27 August 2013

Odd. Even for the Potsdam


Below are a number of photographs of slabs of sandstone from Burgess Ward, Tay Valley Township, Lanark County, Ontario.   The area has been consistently mapped as Potsdam Group sandstone, which is from Middle to Upper Cambrian in age. 

The sandstone at this location exhibits two facies: a wind blown facies evidenced by very fine cross bedding, and an aquatic facies evidenced by burrows (including  U-shaped burrows that are Diplocraterion, and single burrows perpendicular to the bedding plane).  The outcrop at this location is a drainage ditch, close to which are a number of piles of sandstone.   Every time I visit I find something interesting. 

First Slab: Photographs Sam_0499, 0500, 0501

These photos are likely of the sole of the slab, as it appears from photo 501 that the sand filled in a depression.  Whether the depression was caused by burrowing or a vortex (caused by wind or water) is not clear.  It is unfortunate that half of the depression is missing as one needs the missing half to tell whether the depression is a spiral.


Second Slab
Both the top and bottom of this slab are interesting.  The top can be determined because of the V-shaped burrowing on one side.

Thin Brown Lines on Top of Second Slab: Photographs Sam_0471 and 0472

While these could easily be recent staining along roots, or staining cause by water seeping along fine cracks, I’ll have to pass this by an ichnologist and paleontologist  before I rule it out as being a fossil.  It would be particularly interesting if it were an algae from the Middle to Upper Cambrian.



[Added September 15, 2022:]   Another possibility is that this is a fossil graptolite.  See the graptolites in Figure 3 in the following paper:
Geyer, G., Landing, E., Meier, S. et al. , 2022, Oldest known West Gondwanan graptolite: Ovetograptus? sp. (lower Agdzian/lowest Wuliuan; basal Middle Cambrian) of the Franconian Forest, Germany, and review of pre-Furongian graptolithoids. PalZ (2022). 
https://doi.org/10.1007/s12542-022-00627-5



Sole of Second Slab
White polygonal  pattern within troughs in ripple marks: Photographs Sam_0507 and 0487



 




A number of the polygons are hexagons, but many are not.   The sides of the polygons are about 5 mm in length and about 2 mm thick.    Normally one would think that a polygonal pattern found on the bedding plane of a sedimentary rock is made by the infilling of desiccation cracks.   However, there are two reasons why the polygonal shapes in the photos  may not be desiccation cracks.  First,  this rock is sandstone and sand on drying doesn’t contract by the amount required to form the polygons shown in the photos.   Second, the sides of the polygons are  ellipsoidal to  cylindrical in cross-section and resemble burrows.

Is this  a trace fossil somewhat like Paleodictyon?  Possibly.  Paleodictyon consists of a network of hexagonal meshes and has been found in rocks ranging in age from the Cambrian to recent times.   Photographs of Paleodictyon can be found on Wikipedia  and by simply searching the word in Google images   (See, for example:  http://en.wikipedia.org/wiki/Paleodictyon
 http://hexnet.org/content/paleodictyon  )   The polygonal pattern on the slab that I have found resembles a number of the examples of trace fossils that others have identified as Paleodictyon.
   
Another possibility for the polygonal  patterns is that they are evidence of microbial mat shrinkage cracks.

Crystals on Sole of Second Slab: Photo Sam_0506 (and above two photos)

These crystals are interesting.   They are not calcite, as they don’t effervesce in dilute acid.  From the colour and luster they appear to be gypsum, but the crystal system appears to be wrong for gypsum.   I might have to beg a favour and pass a sample to a friend with access to a scanning electron microprobe.







Third Slab: Microbial Mat Shrinkage Cracks

The next photo, Sam_0510, shows three crescent shapes in the troughs of ripple marks in sandstone.   I believe these curved shapes  to be evidence of microbial mat shrinkage cracks (see my blog posting from November 5, 2012).




Fourth Slab: Burrowing in Ripple Marks: Sam_0475

I believe this to be burrowing as the hand specimen shows one sandstone tube going under the other.  (I admit that the photo could be clearer.)









Fifth Slab: Diplocraterion: Sam_0464

I’m including this photo, not because the trace fossil is odd (it’s fairly common), but because I found a sample that shows a good cross-section of three Diplocraterion traces.  (The top of the slab is on the right hand side of the photo.)







Christopher Brett
Perth, Ontario

Monday, 12 August 2013

The Trace Fossil Diplichnites – A New Occurrence in Eastern Ontario

 The trace fossil Diplichnites was named by Professor Dawson of McGill University in a paper presented about 140 years ago.   It is a trackway that consists of two parallel rows of blunt to elongate to ellipsoidal, closely spaced tracks.   It can be contrasted with the trace fossil Protichnites which is a trackway that consists of two parallel rows of imprints surrounding a medial impression.

Interestingly, the trace fossil Protichnites and the trace fossil Diplichnites are often found at the same occurrence.    For example, Alexander Murray of the Geological Survey of Canada reported on such an occurrence in 1852, the same year  William E. Logan and Professor Owen were presenting the initial papers on Protichnites.  

Various researchers have commented on the association of Protichnites with Diplichnites.  A few have suggested that “the Diplichnites may have been undertracks that penetrated to the underlying layer of sediment, and the fossil trackways thus produced on the top surface (preserving the impression of the dragging tail) were Protichnites” (Wikipedia).     In contrast, others suggest that the Diplichnites tracks occur on the surface.  For example, a recent paper discussing a few Diplichnites trackways in the Potsdam Group sandstones in Quebec mentions that  “Examples with pushback mounds and examples that occur on bed surfaces with adhesion structures are not likely undertracks; their lack of central drag marks suggest that some tracemakers held their tails aloft...” (Hagadorn, Lacelle and Groulx, 2012).   A third possibility is that the tracksways grade into one another.    This was noted by a researcher who reported that  “Several tracks of  Diplichnites are also present, with a medial drag mark appearing in places, grading into  Protichnites.” (Charles. T. Hoxie, 2005).

Below I’ve provided photographs of specimens of Diplichnites trackways from the same outlier of Potsdam Group sandstone between Kingston and Perth where I found the specimens of Protichnites mentioned in my last blog posting.

Photos SAM_0491  and SAM_0492 were taken of the same slab.  They show a Diplichnites trackway (two parallel rows of  tracks) crossing ripple marks.   This is likely the sole of an overturned slab, as the footprints are in positive relief.



Photo SAM_0435.JPG is a different slab.    It clearly shows two parallel rows of tracks.






Photo SAM_0438.JPG  is a  specimen  that  was collected close to the specimen shown in Photo SAM_0435.JPG.  There is one good  line of circles (arguably paired  with another line of circles),  plus     crossing lines of  circles,  plus numerous  other circles.




  

Below are photos   SAM_0495 and SAM_0497 of two slabs that might bear the trackway Diplichnites.






       

Christopher P. Brett
Perth, Ontario

Tuesday, 9 July 2013

A New Occurrence of Protichnites in Potsdam Group Sandstone near Kingston, Ontario

Below I’ve provided photographs of slabs of sandstone bearing the trace fossil Protichnites that I collected on July 4th with Wayne Jackson. The specimens were collected from a quarry in an outlier that has been mapped as Potsdam Group, and is considered to be Cambrian in age.  The specimens belong to the Nepean (Keeseville) formation of the Potsdam Group.

The first two photos show three specimens that were offered to the Miller Museum of Geology at Queen’s University and were picked up by the Museum Curator on July 5th. The other photographs are closeup shots of the specimens, some as they were awaiting pickup and others as they were found.  

Each of the Protichnites trackways is roughly 16 to 17 cm ( 6 ½ inches) wide and cuts across ripple marks in the sandstone. In the first two photos the slabs at the top and bottom are the natural cast in the sediment laid down on top of the original trackway, while the middle slab records the original trackway.   The Protichnites trace fossil is a trackway that is believed to have been made by a creature with multiple legs and a tail, with the central furrow in the trackway being a tail drag mark. (The furrow appears as a ridge in the cast.)  In the  specimens in the photographs the central furrow is 3 to 4 cm wide and some of the footprints are up to 1 cm in diameter.













This is a new occurrence of Protichnites in the Potsdam Group Sandstones and was found near Kingston, Ontario.

I should thank my wife for meeting me for coffee on July 4th and encouraging me to take the rest of the afternoon off to go look for fossils. Without her encouragement I might have stayed in the office and worked.


Christopher Brett
Perth, Ontario

(July 12th, 2013 Addendum :   Since posting the above I have been contacted by a friend, Dave Lowe, who is studying the Potsdam Group, who has told me that in addition to the Chippewa Bay member this outlier also exhibits a younger facies similar to the Nepean Formation near Ottawa, with an angular erosional unconformity between the two.   I was wrong in assigning the specimens that I collected to the Covey Hill Formation.  [ April 26, 2023, Addendum:] When I originally wrote  this posting I relied on Sanford and Arnott (2010) and identified the sandstone as the Chippewa Bay Member, Covey Hill Formation, of the Potsdam Group.  In July, 2013 Dave Lowe told me that the outlier also exhibits a younger facies similar to the Nepean Formation near Ottawa.   Now I would clearly identify the sandstone where the specimens were found as Nepean (Keeseville) formation as I found Protichnites, Diplichnites, Climactichnites and the basal, U shaped, part of Arenicolites or Diplocraterion  fossils in this sandstone.    ]

Thursday, 20 June 2013

A Few Trace Fossils in Potsdam Group Sandstones of Eastern Ontario

The Potsdam Group sandstones and conglomerates generally form the basal layer of Paleozoic rocks overlying the Precambrian Shield in Eastern Ontario. The sandstones are thought to be middle to upper Cambrian in age, are generally barren of body fossils (they yield the occasional Brachiopod), but contain abundant trace fossils. The most common trace fossils found in the Potsdam Group sandstones in Lanark County are worm burrows, including burrows perpendicular to the bedding plane (with Diplocraterion and Skolithos being the most common that I've found) and burrows parallel to the bedding plane. (My posting on October 1, 2012 is a field trip to eight outcrops near Perth, where seven of the outcrops are Potsdam Group sandstones that exhibit mostly Diplocraterion but also  possible Arenicolites burrows.) The most famous trace fossils to come out of Lanark County are Climactichnites trails and Protichnites trackways. However, only one quarry in Lanark County has yielded those fossils.

The Potsdam Group sandstones outcrop south of Perth down towards Brockville and down towards Kingston. Those sandstones also exhibit trace fossils, with the sandstones near Sunbury yielding museum quality specimens of Protichnites trackways and Climactichnites trails.

This past weekend I headed south to take photographs of sandstone outcrops, noted some interesting trace fossils, and went back yesterday to collect a slab of rock. Below are a few of my photos of slabs of rock found south of Lanark County.

The first two photos, Sam_0382 and Sam_0383  show a ridge that I suspect is a surface trail beside ripple marks,  where the ridge is similar to the pushed up  lateral ridge for a Climactichnites trail. (The ridge is a surface feature.)




The next three photos, Sam_0354 , Sam_0356  and Sam_0361, are from the same slab .   These show a trace fossil that is a trackway that  extends across the slab .  It is arguably the trace fossil Diplopodichnus, which is a trackway consisting of a pair of longitudinally continuous lateral furrows.








The next two photos, Sam_0358 and Sam_0359, were taken of a different slab of rock, and show two curved grooves. If a reader can provide a name to attach to this trace, please let me know.  My best guess: a bilobate trace, which consists of an  meandering trench bounded by a ridge of excavated sediment on either side.


The last  photo, Sam_0379, shows a narrow burrow parallel to the bedding surface of a different slab  where the burrow cuts across ripple marks.  This burrow is more like a cylinder or tube.






The above photos are of loose slabs of rocks at an outlier   that was mapped as part of the Covey Hill Formation of the Potsdam Group in 2010 by B.V. Sanford and R.W.C. Arnott. (Stratigraphic and structural framework of the Potsdam Group in eastern Ontario, western Quebec, and northern New York State; Sanford, B. V. and Arnott, R. W. C. (2010); Geological Survey of Canada, Bulletin 597, 2010)


Christopher Brett
Perth, Ontario

(July 12th Addendum:   Since posting the above I have been contacted by a friend who is studying the Potsdam Group, who has told me that in addition to the Chippewa Bay member of the Covey Hill Formation  this outlier also exhibits a younger facies similar to the Nepean Formation near Ottawa, with an angular erosional unconformity between the two.   Accordingly, I may have been wrong in assigning the specimens that I collected to the Covey Hill Formation. ]

Wednesday, 12 June 2013

Perthite, Part 2

In my posting last January 14th I set out where to find what is believed to be the type locality for Perthite.

In February I received an email from Luis Sánchez-Muñoz, a researcher with the Institute for Ceramics and Glasses in Madrid, Spain, who identified himself as a geologist who had being doing research on alkali feldspars from pegmatites since 1989, said that he would be visiting Ontario and Quebec to collect specimens of alkali feldspars from famous pegmatites, and that he would be visiting to collect specimens from the type locality. Later I received an email saying he would be joined by Professor Robert Martin of McGill University.  On June 5th I was pleased to welcome them to Perth and provide them with a selection of specimens of Perthite from which to choose. Surprisingly, Luis Sánchez-Muñoz only wanted two. Not surprisingly, he chose two specimens showing two directions of good cleavage.

For those interested in perthitic feldspars a recent paper by Luis Sánchez-Muñoz and a number of co-authors is available over the internet. The paper is entitled The Evolution of Twin Patterns in Perthitic K-Feldspar from Granitic Pegmatites, and was published in the August, 2012 edition of The Canadian Mineralogist, Volume 50, No. 4, pages 989-1024. Figure 21, which is a schematic model for a ten stage general evolutionary sequence of transformations in perthitic K-rich feldspar, with indications of twinning and exsolution, and the explanation in the paper, are interesting, as the authors develop a process that ties the development of twinning patterns into the formation of exsolved Albite.

Luis Sánchez-Muñoz and Professor Martin mentioned that they hoped to visit a number of other pegmatite localities in Lanark County, including the famous Bathurst mine. Readers who are mineral collectors will be likely be aware of the mine, as it was Ontario’s second largest feldspar mine (producing 106,018 tons of feldspar), is listed in at least two of Ann Sabina’s mineral collecting guidebooks, and is easily accessible from Perth. (It is on the northeast side of Old Mine Road, which connects McVeigh Road to Bathurst 9th Concession Road.) It has been forty years since I was there, and I can’t help thinking that it’s probably worth a visit, as it is only 12 kilometers from Perth and there are at least four other abandoned feldspar mines in pegmatites in that area.

When they left I could not help wondering if Professor Martin knew what he had signed up for. An article on the web describes a visit in August of 2010 by Dr. Luis Sánchez- Muñoz to Colorado, where he visited 23 pegamites in five days in pursuit of samples of microcline feldspar. (See: Twenty three pegmatites in five Days, a Colorado field trip saga by Peter J. Modreski and Luis Sanchez-Munoz, an Abstract at the 32nd Annual New Mexico Mineral Symposium
http://geoinfo.nmt.edu/museum/minsymp/abstracts/view.cfml?aid=378 )

Since I posted my blog last January, two points on Perthite have caught my eye. First, I was scanning the second edition of Deer, Howie & Zussman’s book Rock-Forming Minerals, Volume 4A, Framework Silcates - Feldspars, and couldn’t help but notice that they mention (at page 5) that "Perthite takes its name from Perth, Quebec, an early locality." That statement is of course wrong, as Perthite takes its name from Perth, Ontario.

Second, I noticed an analysis and description of Perthite from the type locality near Perth, Ontario in an article by Charles H Warren entitled A Quantitative Study of Certain Perthitic Feldspars, that was published in 1915 in Volume 51 of the Proceedings of the American Academy of Arts and Science, starting at page 139. In his paper Charles Warren compared specimens of Perthite from two localities in Canada, four in the United States and two in Finland. This is Charles Warren’s analysis of Perthite from the type locality near Perth:

SiO2         66.50
Al2O3      18.40
Fe2O3        1.05
MnO       Trace
MgO          .07
CaO           .03
K2O        8.77
Na2O      5.40
H2O         .20
Total   100.69      Sp. Gr. 2.597


He estimated that it contained 51.9% Microcline by weight and 47.3% Albite by weight.

Charles Warren provided this description of his specimen from Perth, Ontario:

"This specimen, from the original locality, is the richest in albite of any of the feldspars studied. It consists of a rather dark reddish-brown microcline intergrown with about an equal amount of a light red to almost white albite. The red color is due to the presence of exceedingly minute crystal scales of hematite which are chiefly contained to the microcline. They are usually arranged along definite crystallographic directions. Some hematite is found along fractures in the albite, or is more irregularly placed. ... The albite lamellae seldom exceed 1mm isn width while a commonly observed width is 0.5 mm. The microcline bands will in general average broader than the albite. The orientation of the bands is fairly uniform parallel to the usual direction, but there is a common tendency to bend off toward the direction of the prism and often many short bands coalesce along this same direction. Pinching and swelling, branching and coalescing, often in a very complex fashion, are common particularly in certain areas. The albite forms minutely pointed surfaces of contact with the microcline as a rule. The microcline sometimes shows very distinct polysynthetic twinning but more often this is faintly developed and is often not visible at all."

Charles Warren was limited by the technology of his day: microscopic viewing of thin sections, and chemical analysis of bulk samples. It will be interesting to see what Luis Sánchez- Muñoz finds with current analytical techniques: polarized light optical microscopy, electron probe micro-analysis, scanning and transmission electron microscopy, cathodluminescence imaging, micro-Ramon spectroscopy and nuclear magnetic resonance, all techniques mentioned in his paper that I referred to above. It was nice to assist a visitor from Spain, and it will be interesting to read the results of his research.

Christopher Brett
Perth, Ontario

Monday, 6 May 2013

On the trail of Climactichnites wilsoni - Part 3: A quarry about a mile from Perth as the town existed in 1859


I have found an overgrown, abandoned small quarry that is about a mile from the town of Perth as the town existed in 1859 at the edge of the Blueberry Marsh on property that was owned in 1859 by Mr. James Glen, and that lies in Concession III of Drummond Township. The rock in the quarry is flat lying white Nepean sandstone (Potsdam Group). Is this the quarry described by Sir William Logan where Dr. James Wilson and Mr. Richardson collected specimens of Climatichnites and Protichnites in the period from 1859 to 1882? Possibly. One side of the quarry is a sandstone ridge about 1.5 meters high and at least 15 meters long. Three other sides of the quarry meld into the Blueberry Marsh. The base of the quarry is about 15 meters by 10 meters and when I found the quarry this past winter was flooded and frozen. The owner of the property tells me that the base of the quarry, which in summer is a pond, is over a meter deep, half filled with water and half filled with silt.

The following photograph shows the quarry on January 27.


According to the present owner of the property, rock from the quarry was used to build the sandstone farmhouse that is on the property. Another source reports that the farmhouse, identified in that publication as the "Glenn House", was constructed in 1848. Current residents of Perth would identify the farmhouse as the Ryan Farm, as the Ryan family farmed the property for many years and still occupy the farmhouse. In the mid-1800's various families with the surname Glen farmed the property and it was known as the Glen House.

The following photograph shows the quarry on February 1.


The quarry meets the following criteria set out in Logan (1860) and (1863):   it is composed of fine grained Potsdam Sandstone (which in Ontario we would now call the Nepean Formation of the Potsdam Group), the quarry is at least three feet deep, the beds in the quarry are flat lying, the quarry is about a mile from Perth as the town existed in 1859, the owner of the property in 1859 was either Mr. Glyn (Logan 1860) or Mr. Glen (Logan 1863), and the quarry is in Concession III of Drummond Township. The quarry is not in Lot 6 of Concession III, where Logan (1863) said the quarry was located, but in Lot 3. However, as noted in my blog posting that is part 2 of this series, Sir William Logan never visited the quarry, neither Mr. Glyn nor Mr. Glen owned property in Lot 6, and the most recent geologic mapping of Lot 6 suggests that Lot 6 is March Formation rather than Nepean sandstone .


The quarry also meets the following criteria for the quarry set out in an article written for Perth Historical and Antiquarian Society in about 1900: it is in the Blueberry Marsh on property owned by Mr. James Glen when Dr. James Wilson first found the specimens that Sir William Logan later named Climactichnites Wilsoni.

While I believe that this is likely the quarry that yielded the first slabs with Climactichnites wilsoni, it can only be verified as that quarry if it yields additional specimens of Climactichnites wilsoni (or perhaps Protichnites).  

When I visited the quarry the last week of January and first week of February the ground was frozen and partially covered by snow. It was not possible to pry specimens out of the ground or moss off the rocks. A later snowfall buried the quarry in over a foot (30 cm) of snow. Two weeks ago the property owner allowed me to take a group of geologists to visit the quarry, and the five of us spent two hours stripping moss and soil, and then examining the rock that we had exposed. This introductory search did not reveal the trace fossils of most interest. The problem is that the quarry is overgrown and covered in soil and moss, and we do not know the layer where the trace fossils of interest can be found. We stripped away some of the soil and moss, which is generally about 3 - 8 cm thick, uncovering about 4 to 6 square meters of horizontal and vertical surface. In the sandstone we found vertical worm holes, which Dr. Donaldson identified as skolithos, and some small angular features that he thought might be traces of parts of microbial mats. There is very little overburden and glacial striae are visible on the surface rock. Cross-bedding is visible in one section of sandstone.

Below are three photographs that I took while at the quarry on April 23rd. The first shows Dave Lowe at an initial stage of pulling moss and soil off the ridge that is a side of the quarry. The second shows Dr. Dalrymple, Dr. Donaldson and Dave Lowe examining an area that had been cleaned. The third shows what might be the most interesting feature that we uncovered: a lensoid/wedge shaped vug on a vertical rock face, with a v-shaped feature running off the bottom right hand side. The v-shape is possibly a trace of a burrow. The lensoid/wedge shape is open to various interpretations. What it is not is a cross-section of a climactichnites wilsoni track. I suggested a burrow, but thus far no one has agreed.




Getty  and   Hagadorn (2008)  recognized two behavioral variants of Climactichnites, with Climactichnites wilsoni  representing surface-produced trails, while Climactichnites youngi represents burrows produced below the surface. Figure 6  in Getty and Hagadorn (2008) shows three photographs of a Climactichnites youngi specimen from Quebec.  Their third photograph is a cross section of the Climactichnites youngi burrow, which appears as a lensoid wedge-shaped sediment infill, much like my photo above. 

Only further investigation will reveal whether the quarry that I have found is the one where Dr. James Wilson first found the trace fossil Climactichnites. However, it fits many of the criteria laid down by Sir William Logan and represents a good chance at being the quarry.

Below I have laid out how I found the quarry.

While searching for quarries in Drummond Township I looked at the book A History of Drummond Township, by John C. Ebbs, published in 1999. In the chapter entitled Fine Stone Homes of Drummond, Ebbs mentions a stone house on the E1/2 Lot 3, Concession 3 and that "It is believed the house was built by the owner, Mr. Glenn, c. 1848." No photo of the house appeared in the book. Driving around the southern third of Lot 3 I found an old stone house on the north side of Dufferin Road on the west half of Lot 3 that I thought might be the old ‘Glenn’ house. The house is constructed of white sandstone. Below is a photograph of the farmhouse. Stones in the walls exhibit the trace fossil diplocraterion.



I looked at the Registry Act pages for Lot 3, Concession III for the Township of Drummond. The Registry page for the West Half of Lot 3, Concession III reveals: (A) that by Quit Claim Deed dated March 12, 1844 Roderick Matheson granted to James Glen the North east half of the west half of lot 3; and (B) that by separate deeds dated from 1831 to 1845 Oliver Glen acquired other parts of the west half of lot 3. Their presence on Lot 3 is confirmed by the 1851 census for Canada West (now Ontario), which I found online, which shows that James Glen owned 76 acres and Oliver Glen owned 24 acres in Lot 3, Concession III of Drummond Township.

While at the Lanark Archives in Drummond Center in early January I was shown an article by Clyde Bell in a 1963 edition of the Perth Courier. Clyde Bell, at the time he wrote the article, was the Perth Museum’s director of information. Most of the article talked about Dr. James Wilson and the founding of the Perth Museum by Archie Campbell. Part of this article talked about Dr. James Wilson making a discovery on a farm belonging to John Glenn, in the blueberry marsh, of a fossil that was identified in Montreal as a mammoth mollusc. While some parts of the article are a bit bizarre, it seemed to describe the finding of Climactichnites, and to have been based on a conversation with a gentleman who as a young lad had accompanied Dr. Wilson when he found the fossil. The article concluded with Clyde Bell commenting "And by the way, we would like to know which farm in Drummond Township was formerly owned by John Glenn." When I read that article I wondered if"John Glenn" was a mistaken reference to the U.S. astronaut who was the first American to orbit the earth. In all likelihood it was, as John Glenn orbited the earth in 1962.

Subsequently I Googled key words from Clyde Bell’s article. This turned up a very similar article on The Lanark County Genealogical Society’s web page. The article is entitled Mining in Lanark County and bears the comment "This undated, unsigned typescript was probably written for the Perth Historical and Antiquarian Society, about 1900." A small part of that article describes the finding of Climactichnites, and again (and, more believably, given its date) appears to have been based on a conversation with a gentleman, Mr. John Hart, who as a young lad had accompanied Dr. Wilson when he found the fossil. One point that is worth noting is that while Clyde Bell’s article referred to the farm of "John Glenn", the original article from about 1900 referred to the farm of "James Glenn." Here is the part of the original article from "about 1900" that deals with the finding of Climactichnites:

"Dr. Wilson's practice led him over a large range of country. He took his hammer with him, and many a bag of stones was brought in for him by the farmers. Some of these he sent to the museum in Montreal, and they have since been removed with the rest of the collection to Ottawa.

What was to him his greatest discovery, was made on the farm of James Glenn. It is supposed the famous blueberry marsh was once a lake. The centre of it is depressed, and the hard ground surrounding it shows signs of ripple marks in thin strata from an inch or less to three inches in thickness. In these the Doctor thought he saw the trunks of fallen trees of a tropical climate. ... He sent specimens ten feet high to Montreal, which were examined by experts and declared to be something, that translated means "first tracks", the tracks of some mammoth mollusc."

I believe that article describes the large specimen of Climactichnites collected by Mr. Richardson in 1859 that hung in Sir William Logan’s office and measured about 10 feet by 7 feet.

If Clyde Bell had framed his question "Do any readers know which farm in Drummond Township was formerly owned by James Glenn?" or as "Do any readers know which farm in Drummond Township adjacent to the Blueberry Marsh was formerly owned by James Glenn at the time Dr. Wilson found the first specimens of Climactichnites?" perhaps he would have received the answer that a "James Glen" had owned such a farm on the North east half of the west half of lot 3, Concession III.

I decided to test my belief that it was worth looking for a quarry on property that was owned after 1844 by James Glen that falls in the North east half of the west half of lot 3, Concession III, Drummond Township where the Blueberry Marsh encroaches on the farm, and identified the most likely location using Google Satellite view. On a sunny, refreshing (minus 11 degrees Celsius) day in January I went for a hike to look for a quarry in the Blueberry Marsh and within a few minutes of arriving at the spot I had identified, found angular pieces of fine grained white sandstone and the side of what I believed to be an overgrown, moss encrusted, shallow quarry. The snow, ice, frozen moss and frozen ground made looking for specimens difficult, and I found none exhibiting Climactichnites or Protichnites. After a few warm days at the end of January had melted more of the snow, I went back on a frigid day in February to again visit the quarry and take additional photographs.

I should add that my wife accompanied me on my first visit to the quarry in late January. While I had asked four others whether they wanted to go for a hike in the Blueberry Marsh to look for a quarry, all of them were too busy, and a few were busy until April. And there wasn’t even that much snow on the ground.

Further visits to the quarry are planned with a number of geologists that have expressed an interest in visiting the quarry. I will post if we find the trace fossils of most interest.

Christopher P. Brett
Perth, Ontario

[Addendum: April 26, 2023: I added the references to Getty and Hagadorn's paper.]

Reference
Getty, Patrick Ryan and James W. Hagadorn, 2008
Reinterpretation of Climactichnites Logan 1860 to Include Subsurface Burrows, and Erection of Musculopodus for Resting Traces of the Trailmaker. Journal of Paleontology Vol. 82, No. 6 (Nov., 2008), pp. 1161-1172


Thursday, 18 April 2013

Glacial Erratics and Eskers in the Township of Lanark Highlands, Lanark County, Ontario

About 79 thousand years ago the Wisconsin ice age started, glaciers formed, advanced and retreated, and at their maximum extent covered most of Canada and extended down into the United States. Lanark County was covered by a glacier two kilometers in thickness. When the glaciers finally retreated from Eastern Ontario about 11,000 years ago they left behind ample evidence of their former presence in Lanark County including eskers, glacial till, glacial striae and glacial erratics.

One of the best places in Lanark County to see evidence of the glaciers is in the Township of Lanark Highlands, particularly along County Road 12 from Playfairville to McDonalds Corners, and along Highland Line, a road off County Road 12 that takes one to Wheelers Pancake House, Sugar Bush and Maple Syrup Museum. At least four commercial sand pits are visible when driving along County Road 12 and Highland Line. The sand in these deposits was left by the glaciers, probably as eskers and fluvioglacial deposits. Also of interest are the glacial erratics that are strewn around the countryside. The hiking trails at Wheelers, which are open year round, provide ample opportunities to view the glacial erratics. The hiking trail that starts directly behind Wheelers Maple Heritage Museum exhibits hundreds of rounded erratics, many in the order of a meter in diameter. However, the largest erratics can be found adjacent to the road into Wheelers. The photographs below show some of the bigger erratics. The person in the photographs is just under five feet (1.5 meters) tall.





The restaurant at Wheelers, the Maple Heritage Museum, a second Museum displaying Vern Wheeler’s collection of over 300 ‘antique’ chainsaws, and the hiking trails are all open year round, seven days a week, from 9 am to 3 pm.  

 Wheelers is worth a visit just for the pancakes and maple sausage. It’s worth visiting to see the two museums. It’s worth a visit if you like to hike (particularly in the fall when the leaves are changing colour). And it is worth a visit if you are interested in glacial erratics and glacial deposits. There is no doubt that the best time to visit Wheeler’s is when the sap is running in the spring, and maple syrup is being made. I think you’d be hard pressed to find someone in Lanark County who has not been to Wheelers for a pancake breakfast. However, the best time to see the glacial erratics is after the snow has melted.

Here is a link to Wheelers: http://www.wheelersmaple.com/


The surficial geology of much of Lanark County was mapped by the Geological Survey of Canada a little over two decades ago. The sand deposits around Wheelers were mapped as glacialfluvial deposits (stratified sediments deposited at or near the glacier margin by meltwater streams). Below are extracts from two maps of the surficial geology issued in 1992 by the Geological Survey of Canada. The first extract shows the surficial geology along County Road 12 running from Playfairville to McDonalds Corners (which is off the left hand margin of the first extract) . The esker that appears on the map as a row of chevrons can be seen from the road. The second extract is to the west of the first and shows the continuation of the esker south of County Road 12 and running roughly following Highland Line towards Wheelers (which is marked on the map with a "W" in a white box).










On the maps the Unit R (light pink) is Precambrian Rock; Unit 1a (dark green) is a Glacial till blanket; Unit 1b (light green) is a Glacial Till Veneer; Unit 4b (dark purple) is Littoral and Nearshore Glaciolacustrine Deposits (gravel, sand, clay); and Unit 7 (grey) is Organic deposits (i.e., muck, peat, bogs, fens, swamp).


Download Sites for Maps
If anyone is interested in looking at the whole of the maps, they can be downloaded free of charge from the Geological Survey of Canada Web site.

Surficial Geology, Perth, Ontario
Kettles, I M (1992), Geological Survey of Canada, Map 1800A,
doi:10.4095/183815

Surficial Geology, Sharbot Lake, Ontario
Henderson, P J, and Kettles, I M (1992)
Geological Survey of Canada, Map 1799A,
http://geogratis.gc.ca/api/en/nrcan-rncan/ess-sst/f1c68435-ee75-51cf-bf46-d8cc6a4ffd2e.html

Anyone wanting to look at the maps as an overlay on Google Earth should consult:
http://www.ontario.ca/rural-and-north/surficial-geology-southern-ontario
Surficial Geology of Southern Ontario
This provides a layer on Google Earth which depicts the distribution and characteristics of surficial deposits across southern Ontario.


Further Reading
The following publications discuss glaciation in Eastern Ontario.

Quaternary History of Eastern Ontario: Impacts on Physical Landscape and Biota
Stephen C. Lougheed and Natalie Morrill
http://opinicon.wordpress.com/physical-environment/quaternary/

Barnett, P. J. (1992), Quaternary Geology of Ontario, Chapter 21 in Geology of Ontario, Special Volume 4, Part 2
Ontario Geological Survey, Special Publication, SV04-02
http://www.geologyontario.mndmf.gov.on.ca/mndmfiles/pub/data/imaging/SV04-02/SV04-02.pdf

Christopher P. Brett
Perth, Ontario