The History of the Scarborough Bluffs

The Famous Scarborough bluffs were named by Lord Simcoe's wife, who said they looked like the chalk cliffs of Yorkshire, near her native hometown of Scarborough england. Only after they landed did they discover that the cliffs were not made of chalk, but compressed white sand.

The Sand was deposited here 70 thousand years ago. At that time, a growing ice sheet had blocked off the st. Lawrence, causing much higher lake levels, similar to that of Lake Algonquin. Plant and insect fossils from the escarpment indicate that much of the Scarborough area was a Boreal delta in a very large glacial river, probably fed from the melt waters of the ever growing Wisconsan Ice Sheet.

Insect Fossils and clays in the formation seem to indicate that the climate was similar to near-tundra boreal forest, resembling a patchwork of spruce groves, with grassy and rocky barren strips. July average temperatures reached a bomby 12 degrees C.

Eventually the glaciers covered the delta, and all the deposits placed by the river delta were crushed together under a kilometer of ice. This Hard packed sand is what makes up the "scarborough formation" that makes up the bluffs.

As the glaciers retreated, Lake Iroquois formed. The glaciers still blocked off the escape route to the St. Lawrence near the present day thousand islands, and so the lake grew. The lake was 30m higher then it is today, and was drained through new york state rather then the St. Lawrence.

Erosion from the lake chopped away at the compressed sand coastline, and as the water level fell, the coast became more pronounced, and eventually became a cliff. Erosional forces like wind, rain, snow, ice, hail and water have made some impressive spires in the sandstone, as well as made some very pretty cliffs.

Manmade fingers jutting into the lake were installed by the city of Scarborough, and later by the city of Toronto after amalgamation to prevent erosion and save the pretty houses from slipping into the lake.

Maps of the Bluffs

A.P. Coleman (1852-1932) was the Head of the University of Toronto’s Department of Geology and a prominent geologist. He was responsible for creating the first maps of the glacial deposits in the Toronto area. In 1903 he determined that cliffs would retreat at an annual rate of .71m. Up until approximately 1950, the area south of Kingston Rd was largely undeveloped. Yet, by the early 60’s urban sprawl had claimed the area, ignoring the warnings of Coleman almost 60 years earlier. It is quite clear from this historical record that the area near the cliffs should not have been developed to the extent it has been. The Toronto Regional Conservation Authority (TRCA) was established in 1957 in response to the damage caused by Hurricane Hazel. They have been the primary overseeing body that reviews and plans construction at Bluffer’s Park Marina and the slope stabilization programs along the shoreline. The structures they have built along the shorelines are called berms and their intended purpose is to halt the process of erosion in the Bluffs, solely to protect the houses that are built close to the edge of the cliffs. The Bluffs erode and collapse, leaving piles of sand and clay at their bases. The lake washes up against these shores and removes the sediment. It is this process that created the Toronto Islands and many of the beaches along the lakeshore. Now, the marina prevents sediment from being washed away, and the waters there need to be dredged. As the berms are put in place, the water can no longer wash away the sediment. This results in the cliffs becoming vegetated, and the process of erosion being halted or slowed.

It is easy to understand the confusion regarding the issue of conservation in this area. Many people look at the greened cliffs and think that this is a good thing, as it seems more natural. In fact, it is a destruction of the natural ecosystem and cycle of this area, which relies on the patterns of erosion to maintain its balance. One area that Dr. Eyles remembers fondly is the Bellamy Ravine. Now land filled with the rugged Doris McCarthy Trail installed, he recalls how it was once referred to as the “Grand Canyon of Scarborough”. He says that it would take a whole day to hike to the bottom, and the geological treasures there were significant. Because of the erosion processes, scientists used to come from around the globe to study the visible layers from different eras. Now, with the vegetation of the cliffs and the major ravines now land filled and tamed, the area has become a major loss to the world’s geological record. As we can see, conservation in this area may have been lost for good. However, the goal of re-naturalization is still attainable. There are still ravines that have not been land filled, and faces of the cliffs that are still actively eroding. Not to mention the fact that this area is a habitat for many, many species and a major migration route for a diverse and large group of birds and butterflies. I wonder how we will face future generations to explain to them how little value we have placed on some of the planet’s most beautiful and wild places.

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