What’s New in Potsdam Sandstone?  (And a few that I missed)

This posting mentions articles published  since my June 1, 2021 posting, and few  that I missed previously.  

Lowe,  DeSantis,  Arnott, and  Conliffe (2022) report on silcrete in the Potsdam in upper New York State.  They postulate  groundwater silcrete linked to brine migration in a continental rift zone as an alternative to the near-surface model of silcrete.   More particularly,  a groundwater silcrete from Upper Cambrian strata of the Potsdam Group is described and interpreted to be formed in a rift where Cambrian fault reactivation coincided with silcrete formation.   They state “The silcrete horizon documented here caps strata of the middle allounit, termed Allounit 2, and consists of Upper Cambrian braided and ephemeral fluvial quartz arenite and quartzose conglomerate.  Based on its stratigraphic position, formation of this silcrete coincides with terminal Cambrian basin inversion and unconformity development in the Ottawa Graben.  ... The silcrete horizon that caps quartz arenite strata of Allounit 2 crops out over an area of ~0.3 km2 in northwestern New York State. ... The horizon is 8–142 cm thick,”  [ I have not been down to look at their outcrops, but note that I  found a large, meter diameter, angular, loose  block of silcrete in an abandoned March formation quarry about 3 km east of Perth, Ontario.]

David Lowe (2024) discusses the aulacogens of the Neoproterozoic to Ordovician Laurentian Iapetan Margin.   He ties the deposition of the various formations of the Potsdam group into Continental rifting theory.    (Most of his paper doesn’t deal with the Potsdam.)

Daniela Garcia Ramos (2023) looked at the Thermal History of the Frontenac Arch in Southeastern Ontario, Canada Constrained From Low-temperature Thermochronology.  One interesting comment she makes is “On the basis of lithological, stratigraphic, paleontological, paleogeographic reconstructions, and thermochronological evidence, I suggest that ~ 3-4 km thick sedimentary rocks contributed to bury and reheat the rocks of the Frontenac Arch until the late Paleozoic. However, the sedimentary material has been removed by erosion since at least the Mesozoic, and only remnants of the Ordovician and Pre-Ordovician sequences are preserved today.”  Her Figure 2.8 B is a photograph of Potsdam sandstone showing soft sediment deformation/ seismites in the Nepean quartzarenite, a photo that I supplied,   Location: 44.69577°N, 76.30165°W, that had appeared in my October 22,  2015 blog post.

Elliot et al. ( 2025) looked at Potsdam sandstone outcrops in New York to provide insights into folds, deformation bands, and fractures that could influence permeability, heat exchange, and stimulation outcomes of geothermal reservoir targets.  They found that fractures show four chronological Sets A–D, striking NNW, NE, NW, and ENE, respectively. Fracture lengths and heights range from millimeters to tens of meters. Sets A and C macro-fractures, and possibly B and D, contain quartz deposits.  All sets had abundant associated quartz cemented microfractures that also record set orientations and crosscutting relations.  They state that quartz cement deposits—evidence of diagenesis—are the key to identifying attributes of outcrop fractures suitable for extrapolation to geothermal targets in sandstones because they show which fractures formed in the subsurface.

Konstantinovskaya et al. ( 2023)  conducted 3D reservoir simulations of supercritical CO 2 injection  in the  Potsdam Sandstone of the St Lawrence Platform (Gentilly Block), Quebec to predict safe CO 2 injection rates, evaluate reservoir pressure build-up in the presence of sealing and permeable faults, and estimate the gas injection cumulative, in part to estimate the risk of top and bottom seal failure and fault shear-slip reactivation.

Graham A. Young  & James W. Hagadorn (2020) looked at the  facies distribution of fossil jellyfish through time.  Their Figure 1, Plate 1 shows undescribed scyphozoan from a Cambrian arenite of the Potsdam Group, Carrières Ducharme, Québec, Canada; Pointe-du-Buisson/Musée Québéquois d’archéologie, Québec.  Their Figure 1, Plate 2 shows  Domical mouldic medusae on bedding plane surface of a Cambrian arenite in the Potsdam Group, Ausable Chasm, New York,    For the Keeseville Formation, Potsdam Group,  Ausable Chasm, New York, they report numerous medusae, stating that “The fossils are preserved as moulds  in medium-grained quartz arenites, and often appear  as simple circular mounds, but some are twisted or folded, exhibit evidence of transport, or have tripartite or  quadripartite axial regions ... They  are interpreted as scyphozoan medusae, but have not yet  received systematic description. More than 1000 medusae are known, occurring in more than six horizons. Diameters range from about 50 to 660 mm, with an average of  just over 200 mm. The depositional environment is interpreted to have been intermittently emergent, and the  arenites containing medusae have sedimentary structures indicating deposition in very shallow water less than 2 m deep.” 

One that I missed is Minter,  Buatois, Mángano , MacNaughton, Davies,  & Gibling, ( 2016)  who suggest that the eolian beds in Ontario where MacNaughton et al. ( 2002 ) reported  Diplichnites and two varieties of  Protichnites  are similar in age to interfingering eolian dunes in New York State where Hagadorn et al. ( 2011) reported  Diplichnites,  Protichnites , and paired grooves (cf.  Diplopodichnus). They provide photographs of Protichnites and Diplichnites from the eolian beds in Ontario.

I previously gave the citation for Brink,  Mehrtens  & Maguire (2019) but didn’t summarize it.  I haven’t mentioned Landing, Amati, & Franzi (2009).  Both are important.  Brink et al. (2019) describe in detail the  Altona Formation, the oldest unit in Potsdam Group, identifying six lithofacies including nonmarine sheet flood, nearshore bay/estuary, and upper and middle shoreface.   Landing et al. (2009) described fragments of an Olenellid trilobite as well as specimens of Ehmaniella from a unit below the  Ausable Sandstone which led them to suggest that the  horizons should be recognized as a separate unit termed the Altona Formation.    Landing et al. (2009) also  reported occurrences of small Cruziana and Rusophycus trace fossils from their Altona formation.

Christopher Brett

Ottawa

References and Suggested Reading

Brett, Christopher,  2015   Soft-Sediment Deformation (Seismites) in Nepean Sandstone Close to the Rideau Lake Fault.  Blog posting dated  October 22,  2015 https://fossilslanark.blogspot.com/2015/10/soft-sediment-deformation-seismites-in.html

Brett, Christopher,  2016.  What’s New in Potsdam Sandstone?  Blog posting dated  August 5,  2016 https://fossilslanark.blogspot.com/2016/08/

 Brett, Christopher, 2021.  What's New in Potsdam Sandstone? Blog posting dated  June1,  2021 

https://fossilslanark.blogspot.com/2021/06/whats-new-in-potsdam-sandstone.html

Brink, R., Mehrtens, C. & Maguire, H. 2019. Sedimentology and petrography of a lower Cambrian transgressive sequence: Altona Formation (Potsdam Group) in northeastern New York. Bulletin of Geosciences 94(3), 369–388 (18 figures, 2 tables, appendix). Czech Geological Survey, Prague. ISSN 1214-1119.   http://www.geology.cz/bulletin/fulltext/1728_Brink_191208.pdf

Elliott SJ, Forstner SR, Wang Q, Corrêa R, Shakiba M, Fulcher SA, Hebel NJ, Lee BT, Tirmizi ST, Hooker JN, Fall A, Olson JE and Laubach SE (2025)     Diagenesis is key to unlocking outcrop fracture data suitable for quantitative extrapolation to geothermal targets.  Frontiers in Earth Science, Economic Geology,  1 April 2025, Volume 13 - 2025 |      https://doi.org/10.3389/feart.2025.1545052

Garcia Ramos, Daniela, 2023    Thermal History of the Frontenac Arch in Southeastern Ontario, Canada Constrained From Low-temperature Thermochronology.  Masters of Science Thesis. Queen’s University, Kingston, Ontario 206 pages   http://hdl.handle.net/1974/31426  https://qspace.library.queensu.ca/items/c276a99a-078d-45c0-afc1-538e986686c5

Konstantinovskaya, Elena,  Jose A. Rivero, Valentina Vallega. John Brodylo, Peter Coldham

3D reservoir simulation of CO 2 injection in a deep saline aquifer of the Lower Paleozoic Potsdam Sandstone of the St Lawrence Platform, Gentilly Block, Quebec  January 2023 Geoenergy 1(1) DOI:10.1144/geoenergy2022-001

Landing, E., Amati, L. & Franzi, D.A.,  2009   Epeirogenic transgression near a triple junction; the oldest (latest EarlyMiddle Cambrian) marine onlap of cratonic New York and Quebec. Geological Magazine 146(4), 552–566.   DOI 10.1017/S0016756809006013  

Lowe, D.G.,  2024   Aulacogens of the Neoproterozoic to Ordovician Laurentian Iapetan Margin,

Earth-Science Reviews, Volume 255, 104829,

https://www.sciencedirect.com/science/article/pii/S0012825224001569

Lowe, D.G. ,  E. DeSantis, R. Arnott, J. Conliffe, 2022   Groundwater silcrete linked to brine migration in a continental rift: an alternative to the near-surface model of silcrete .  Geosphere, 18 (3) (2022), pp. 1055-1076  https://pubs.geoscienceworld.org/gsa/geosphere/article/18/3/1055/612948/Groundwater-silcrete-linked-to-brine-migration-in

Minter, N. J., Buatois, L., Mángano, G., MacNaughton, R., Davies, N., & Gibling, M., 2016.  The prelude to continental invasion. In G. Mángano, & L. Buatois (Eds.), The trace-fossil record of major evolutionary events: Volume 1: Precambrian and Paleozoic (Vol. 39, pp. 157-204). (Topics in Geobiology; Vol. 39). Springer. https://doi.org/10.1007/978-94-017-9600-2

https://www.researchgate.net/publication/310483425_The_Prelude_to_Continental_Invasion

Yochelson, E.L.  and M. Parrish, 1992    Reconstruction of the enigmatic Late Cambrian Climactichnites.   The Paleontological Society Special Publications , Volume 6: Fifth North American Paleontological Convention-Abstracts and Program , 1992 , pp. 321.  Published online by Cambridge University Press:  26 July 2017  DOI: https://doi.org/10.1017/S2475262200008819 https://www.cambridge.org/core/journals/paleontological-society-special-publications/article/reconstruction-of-the-enigmatic-late-cambrian-climactichnites/3704BDF67A29C82871FD8C394BF468B6

Young, Graham A.  & James W. Hagadorn, 2020  Evolving preservation and facies distribution of fossil jellyfish:  a slowly closing taphonomic window .  Bollettino della Società Paleontologica Italiana, 59 (3), 2020, 185-203. Modena   https://www.academia.edu/48910995/Evolving_preservation_and_facies_distribution_of_fossil_jellyfish_a_slowly_closing_taphonomic_window     

 

Logan’s Original Protichnites Specimens From Beauharnois Were Found in the Collection of the Canadian Museum of Nature

I noticed a recent 2026  article in a leading geological journal which mentioned that Logan’s specimens of Proctichnites from Beauharnois were lost, but that original plaster casts of the specimens had been located in the Amherst College Museum of Natural History.   While the specimens were lost, they were found in 2014 in the collection of  Canada’s Museum of Nature at their research facility in Gatineau, Quebec, indexed with the wrong identification   [Kouphichnium] or not indexed with any identification.   I looked at them on July 29, 2014 with Dr. Robert MacNaughton, Michelle Coyne,  Keiran Shepherd and  Margaret Currie,    

Dr. MacNaughton  gave a talk in 2017 at the Canadian Paleontological Conference in Calgary, Alberta where he described how the specimens were found and the significance of the specimens.  The text of the abstract for his talk mentioned that “most of Logan’s specimens from Beauharnois were rediscovered in the collections of the Canadian Museum of Nature”.   As the abstract is not available online, it  is reproduced below.  

"SIR WILLIAM LOGAN AND THE ADVENTURE OF THE  ANCIENT AMPHIBIOUS ARTHROPOD 

R.B. MacNaughton, C.P. Brett, M. Coyne  and K. Shepherd

  Keywords: ichnology; Protichnites; Cambrian; Potsdam Group; Sir William Logan 

In his first literary appearance, Sherlock Holmes opined that “There is no branch of detective science which is so important … as the art of tracing footsteps.” The study of footsteps has an equally proud pedigree in paleontology. Forty years before the great sleuth made his debut, fossilized trackways produced by a long-vanished arthropod were found at several sites in Cambrian strata of the Potsdam Group at Beauharnois, Québec. Sir William Logan, the founding Director of the Geological Survey of Canada, carefully documented these localities and collected several very large specimens. Logan transported the trackways to the United Kingdom, where the anatomist Sir Richard Owen described them formally in 1852. Owen named the trackways Protichnites, the first time that arthropod-produced fossil trackways were given a formal Linnaean name. Owen documented six ichnospecies of Protichnites, providing detailed, but densely written descriptions illustrated by high-quality lithographic plates. Logan, in a very early example of applied comparative sedimentology, documented sedimentological evidence that the track-makers might have come out of the sea to walk about on land, providing the fullest account of his reasoning in the classic 1863 text The Geology of Canada. Logan’s prescient ideas would be borne out by studies a century and a half later, and Protichnites now provides evidence for the earliest-known forays of animals onto dry land. Recently, most of Logan’s specimens from Beauharnois were rediscovered in the collections of the Canadian Museum of Nature, providing an opportunity to reassess the ichnotaxonomy of Protichnites and to view at first hand some of the evidence on which Logan based his conclusions regarding the environmental range of the track-making arthropod. In honour of the 175th anniversary of the Geological Survey of Canada, this talk will discuss the importance of Protichnites as a record of early non-marine animal behaviour, while celebrating Logan’s pioneering, downright Holmesian work on the subject. "

In fairness to those that didn’t realize that the specimens had been found, I note that the title to the talk did not disclose that the specimens had been found, and that the abstract could not be found online.

Photos of Logan’s specimens of  Protichnites septemnotatus, Protichnites alternans and Protichnites lineatus can be found in my October 17, 2017 blog posting.

I suspect that Logan’s specimens were 'lost' when the Centre Block of Canada’s Parliament Building burned down in February, 1916  (fifteen months after the start of the First World War)  and the Geological Survey of Canada  had to quickly vacate the Victoria Memorial Museum so that Parliament could sit at the museum, and so that offices could be provided for the members of the House of Commons..  Most specimens were crated and moved out within 40 hours of the start of the fire.   Harlan (1916) describes the hurried crating of specimens.  Here is part of his description:

    “The east hall, with invertebrate palaeontological exhibits, similar in size to the other exhibition halls, contained thousands of small and delicate specimens. These were all carefully wrapped, packed and taken away. Forty hours after the beginning of the fire, all the museum specimens and cases had been moved from this part of the building, which was made into offices for the members of the House of Commons.   

    Of the east wing, containing tentative vertebrate palaeontological exhibits, three-quarters were cleared, and these exhibits were stored, with those of the' other quarters, along the walls of the southern half of the hall. This clearing involved not only the moving of small exhibits in cases, but also of such heavy fragile specimens as the titanotherium and the skulls of dinosaurs and mammoths, yet it was all done within two hours after this notification, that is by noon, or in less than twenty hours from the time that the fire broke out.” 

The Victoria Memorial Museum  served as the home of the Parliament of Canada from 1916 to 1920 while the Centre Block was being rebuilt.  I expect that the Protichnites specimens  were just left in storage when the Geological Survey of Canada moved back into the Victoria Memorial Museum in 1920,  and over time the significance of the specimens was overlooked and forgotten.  Or it may have been that the fossil dinosaurs collected in Alberta by the GSC (see Russell, 2012)  were deemed more appealing to museum visitors.

Christopher Brett

Ottawa

Reference and Selected Reading

MacNaughton, R.B., Brett, C.P., Coyne, M., and Shepherd, K., 2017. Sir William Logan and the Adventure of the Ancient Amphibious Arthropod. In: Gouwy, S., and Bell, K. (eds.), Canadian Paleontology Conference Proceedings No. 14, (The Geological Association of Canada - Paleontology Division; St. John’s, NF), p. 19.

 

Brett, Christopher, 2014:  My Hunt for Sir William Logan’s Specimens of Protichnites.   March 7, 2014 blog posting  https://fossilslanark.blogspot.com/2014/03/my-hunt-for-sir-william-logans.html

 Brett, Christopher:  2017  Protichnites, etc. on display at the Canadian Museum of Nature’s Collection and Research Facility.  October 27, 2017 blog posting   https://fossilslanark.blogspot.com/2017/10/protichnites-etc-on-display-at-canadian.html

 Brett, Christopher, 2019  Are Elkanhah Billing’s Specimens of Aspidella Truly Missing, or are they just Hanging Out with Logan’s slabs of Protichnites at the Canadian Museum of Nature’s Research.   March 30, 2019 blog posting   https://fossilslanark.blogspot.com/2019/03/

Brett, Christopher, 2020  Reports of Trace Fossils from the Potsdam Group Sandstones of Ontario, Quebec and New York State  See: subheading:  Logan’s Specimens of Protichnites Were Found

https://fossilslanark.blogspot.com/2020/10/reports-of-trace-fossils-from-potsdam.html

Anonymous,  Charles Mortram Sternberg, Wikipedia, retrieved May 18, 2026

https://en.wikipedia.org/wiki/Charles_Mortram_Sternberg

Russell, Loris S., 2012  History of Palaeontology in Canada.  The Canadian Encyclopedia.  Published Online May 7, 2012, retrieved May 18, 2026  https://thecanadianencyclopedia.ca/en/article/history-of-palaeontology-in-canada

 Smith, Harlan, 1916  The Fire and the Museum at Ottawa.  The Ottawa Naturalist, March, 1916, pages 164-167  https://www.biodiversitylibrary.org/item/28021#page/172/mode/1up