Growing up in Ottawa one of my earliest sources on the geology of the Ottawa area was an article by Alice E. Wilson entitled A Guide to the Geology of the Ottawa District that had been originally published in Volume 70 of The Canadian Field-Naturalist in 1956. The article had been reprinted and was sold as a bound issue through the Victoria Memorial Museum in Ottawa (often referred to as the ‘Dinosaur Museum’, but now properly called the Museum of Nature). It was a great publication. The article summarized the geology, had plates showing the common fossils, provided field trips, contained cross-sections across Ottawa, and contained maps showing faults and field trips. That article in combination with David M. Baird’s book a Guide to the Geology and Scenery of the National Capital Region, Donald Hogarth’s reprinted article from The Canadian Field-Naturalist entitled A Guide to the Geology of the Gatineau-Lievre District, and Ann P. Sabina’s various guidebooks on mineral collecting sites, provided a very good introduction to the geology and collecting sites of the Ottawa area.
Six years ago my wife and I moved to Tay Valley Township, which is south of Perth, and in the southern part of Lanark County. One of the first things I did was to order the geological maps of this area that had been published by the Ontario Geological Survey and the Geological Survey of Canada, and to re-read the chapters covering Eastern Ontario that were in the Ontario Geological Survey’s 1992 publication entitled Geology of Ontario. Over the past few years I’ve been reading the more recent articles that are available online on the sedimentary rocks of Eastern Ontario, Northern New York and Quebec south of Montreal. I was thrilled when in 2010 the Survey published Sanford and Arnott’s Bulletin 597 entitled Stratigraphic and structural framework of the Potsdam Group in eastern Ontario, western Quebec and Northern New York State. Not only is it a good read, but many of the important outcrops noted on the maps are an easy driving distance from where I live.
Towards the end of this summer I decided that I should acquire a copy of the Geological Survey of Canada’s Memoir 241 by Alice E. Wilson that is entitled Geology of the Ottawa-St. Lawrence Lowland, Ontario and Quebec, that had been published in 1946 and covers the Paleozoic rocks of what is now commonly referred to as the Ottawa Embayment. I made that decision because every article and publication that deals with the sedimentary rocks found in Lanark County refers to that memoir. I was fortunate to be able to acquire it online. Having read the book, I wish I’d bought it sooner. This is because Nepean Sandstone, March Formation interbedded dolostones and sandstone, and Oxford Formation dolostones make up the bulk of the sedimentary rocks of Lanark county, and this is the publication that defines those formations. GSC Memoir 241 is also worth buying for the maps, even if they fail to cover much of Lanark county.
However, it is the Bibliography at the end of the book that is the real reason why, sixty-six years after it was published, that everyone reading this blog posting should try to acquire the publication. Alice E. Wilson devotes six and a half pages to a list of articles on the geology of the Ottawa Embayment, and seven and a half pages to an additional listing of articles on palaeontology that cover fossils found in the Ottawa Embayment. There are many of the expected references. These include the papers by Sir William Logan, Owen, Billings and Ami on Climatichnites and Protichnites, Sir William Dawson’s paper on burrows and tracks in Palaeozoic rocks, papers by Logan, Ells, Vennor on geology, and W.A. Parks’ classic on building and ornamental stones found in quarries in Ontario, that I’m sure everyone that has seriously looked at the Ottawa Embayment has read. In addition there are some real gems listed in the bibliography that would be almost impossible to find without these lists, and to my knowledge are not summarized elsewhere.
Some papers listed in the bibliography are of interest for the collector and the amateur interested in Lanark County’s geoheritage. These include, for example, a reference to Samson’s Shoulder Stone, a large glacial erratic found near Perth, and a reference to an abandoned quarry east of Perth that was not mapped by the Ontario Geological Survey when they re-mapped the Paleozoic rocks of Eastern Ontario in the early 1980's .
Other papers listed in the bibliography are potentially of interest to academics, including over thirty by Elkanah Billings, one of Canada’s most famous paleontologists. The most intriguing that I have found so far is one cited by Alice E. Wilson as Billings, E. (1860) Additional Note on the Potsdam Fossils: Amer. Jour Sci. (2) 30, pp 242-243, 337-338. This is a reference to a trilobite found in the Potsdam sandstones of New York which is not referred to in the recent literature. There are actually two articles:
Article XXIV - Description of a new Trilobite from the Potsdam Sandstone; by Frank H. Bradley, with a note by E. Billings (1860), American Journal of Science and Arts, Volume 30, Second Series, pages 241-243
Article XXX - Additional Note on the Potsdam Fossils; By E. Billings (1860), American Journal of Science and Arts, Volume 30, Second Series, pages 337-338.
Here Bradley and Billings report on finding a number of specimens of the trilobite Conocephalites Minutae in Potsdam sandstone at High Bridge, near Keeseville, New York. This may be important because trilobites can sometimes be used to date rocks and trilobites have rarely been found in the Potsdam sandstones.
The above photo shows the drawing of the trilobite from the article. I took the photo of my computer screen when I was looking at the full article on Google Books. Anyone wanting to read the full article should be able to find it by searching with Google.
For those not familiar with Alice E. Wilson (1881 - 1964), the following points are worth noting:
- she was the first female geologist in Canada and the first woman to hold a professional position with the Geological Survey of Canada ("GSC")
- the GSC granted her a leave of absence and she obtained her doctorate in geology from the University of Chicago in 1929 at age 48
- she carried out extensive research on the sediments and fossils of the Ottawa-St. Lawrence lowlands, mapping over 16,000 square kilometers, and was a highly respected expert in the field of paleontology
- when she officially retired from the GSC in 1946, at age 65, five people were hired to replace her
- Dr. Wilson kept her office at the GSC after retirement, continuing to visit and carry out field work, and gave up her office in 1963 at age 82.
My source for the above is an undated National Research Canada fact sheet entitled: Trailblazer – Alice Evelyn Wilson, 1881-1964, First Woman Geologist Left Her Mark in Stone. What this fact sheet fails to mention is that for over thirty years she was the authority on the Paleozoic in Eastern Ontario, and published many papers on the Ordovician fossils and geology of Eastern Ontario.
Happy reading,
Chris Brett
Perth, Ontario
[To Comment: on the line below click on the word "comment" or "comments".]
No comments:
Post a Comment