This Earthcache will take you back million of years to the site of an ancient tropical sea. Fast forward to relatively modern times when a clay quarry to make bricks was founded in the 1880’s. In 1894, University of Toronto geology professor A.P. Coleman made a discovery of international significance at this site – in the North quarry wall, he found fossil evidence of two full-blown ice ages. This is one of the very few sites in the world where climate change can be studied between the last two major glaciations. Evidence from the Illinoian Glaciation (~135,000 years ago) can be found at the very bottom of the North Slope. Above this is the Don Formation (~125,000 years ago) - fossils here suggest that Toronto's climate at that time was slightly warmer than at present. From fossils in the next two layers (Scarborough and Pottery Road Foundations ~110,000-80,000 years ago), there is evidence of a cooler climate, leading up to the Wisconsin Glaciation (~50,000-13,000 years ago). To read more about the formation of the different layers of the North Slope and to see fossils found in this area, visit this link: http://lostrivers.ca/points/BrickworksNorthwall.htm
The posted coordinates will take you to the North Slope of the old quarry wall. Here, you will find a plaque with a diagram of the geology of the area to help you out. After visiting the North Slope, continue South-West along the path to WP1 (the West Wall) at N43 41.234 W079 22.030.
To log this cache as “Found”, please perform the following tasks and email your answers to the CO:
At GZ (North Slope):
1] Estimate the height of the North Slope.
2] With help from the plaque at GZ, estimate how many metres in height are represented by the Wisconsin Glaciation's Sunnybrook Drift deposits. (You may have to stand back a bit to see the layering on the slope.)
At WP1 (West Wall):
3] Here, you'll get a close-up view of geology of the Illinoian Glaciation - compare this to what you observed of the Wisconsin Glaciation at the North Slope. Did you note any differences?
As the Brick Works is home to many fauna and flora, include in your posted log any interesting wildlife you may have seen along your path through the Brick Works. Feel free to post a picture of something interesting you saw on your trip around the paths.