Yup,scratches on the rocks. Don’t know if you’ve ever been to Central Park but most of the “mini mountains” I spoke of have the very same thing. And those scratches,I’ve read,are proof that there was a glacier there.And those glaciers,like most glaciers,have small (and not so small) rocks that they drag along with them and it’s those rocks which cause the scratches.
Yes, I have been there, and yes, I have seen what you mentioned. impressive.
Last glacier, so called Wisconsin glacier reached as far south as south of Indianapolis. Ohio valley was created by flood from melting glaciers.
What is even more stunning is the fact that the glaciers melted in practically no time. Like maybe few years?
The melting of glaciers was accompanied by huge floods, a lot larger that anything we ever experienced.
All the Midwest river valleys were carved by that flood, instanty.