Why would fossils found at the top of a canyon probably be younger than those found at the bottom of the canyon

Bc the older fossils from all the dirt and rain go to the bottom and the younger ones will be found at the top Bc they just died

Because, the layers at the bottom of the canyon are from hundreds of years ago. Because the canyon started from the bottom and went to the top, so the top layers are younger than the bottom. So the fossils at the top are recent animal who died there, the fossils at the bottom are from years ago. I hope this help you. (:

When is this