Meltwater from the glacial deposit at the Oak Ridges Moraine, situated  north of the city, flowed southeast towards Glacial Lake Iroquois, carving through nearly  of soil, alluvial soft sand, gravel, and clay till to form the ravine valleys.
Meltwater from the glacial deposit at the Oak Ridges Moraine, located north of the city, flowed towards Glacial Lake Iroquois, eroding a significant portion of soil, alluvial soft sand, gravel, and clay till to form the ravine valleys.