Toronto Fossil Hunt on Mimico Creek

Mimico Creek carves into the shale
 wall, causing rocks to fall.

This week I have been visiting Mimico Creek, in Toronto's west end. The creek carves into a wall of shale that dates from 455 million years ago. As the water and erosion eats into the wall, slabs of shale fall onto the creek bed where water gets to work, eroding the shale. What's incredible is how many fossils can be found in the rocks. As I walked along, I came across scores of fossils, from ancient mollusks, to tube-shaped imprints which were left by creatures are they burrowed in the mud.

The fossils date from a period when life on land hadn't started yet. The first amphibians crawled onto land around 300 million years ago. These rocks date to 155 million years before that, when life only existed in the oceans. At that time, Toronto was located close to the equator, beneath a warm sea.  So, while I walked along this creek, which is frequented by herons and ducks, with a busy road 100 meters away, I was seeing the remains of creatures which lived almost half a billion years ago. Does it get cooler than that?

Fossilized mollusk from 455 million years ago

There are no dinosaur fossils, unfortunately. Toronto may have had them at some point, but during the last ice age, when the ice was one kilometre high, the glaciers scraped away all the rocks from the dinosaur era. Fortunately, the rocks left by this ancient sea was left intact.

This spot lies south of the Queensway, at Park Lawn ( beneath the bridge). There is a parking lot next to the Royal Bank. The water is quite shallow, so once you get down to the creek, it is easy to walk back and forth across the stream if you don't mind getting your feet wet. This creek can get quite deep during any rain storm, so only try this when the water levels are low.

Fossilized wave ripples

Stephen Milton is a freelance writer and documentary film producer. To see more nature photos, please visit www.torontonature.com. Also, to get daily nature photos, sign up on Facebook to the Toronto Nature diary.