From 40,000 to 21,000 years ago, the Edmonton region was a relatively flat savanna. Fossils found between Fort Saskatchewan, Sherwood Park, and Clover Bar, tell us that hyenas, paleo camels, and bison roamed the grassy plain. They were much larger than the ones we know today.
Glaciers then advanced from the East, covering this area with ice up to 2 kilometers thick.
The river valley you see today formed after the last ice age ended, about 12,000 years ago. Warming climate brought big changes. Large animals returned, and water from melting glaciers eroded the plain into a valley. The water flowing across the plains started to cut through layers of sand and gravel. As the river bed moved deeper, the layer at the top became a terrace. The river kept moving, carving new 'steps; in the valley wall. The river reached its current level about 8,500 years ago, and then started eating away at the valley sides.
In order to log this earth cache as found, please email us the answers to the following questions:
1. Why did the large prehistoric animals leave this area?
2. What happens, to determine the width of the river valley?
3. As you look across at the opposite river bank, do you see any indication of terracing?