I saw a documentary not long ago which said that there's irrefutable evidence that Central Park (the one in Manhattan) was,not all that long ago,completely enveloped by a glacier that was something like 2,000 feet thick.
I think you CAN see ice polished rocks still there.
If the NHYT prints it; iut has GOT to be true!!
http://www.nytimes.com/2005/09/14/nyregion/the-very-cold-case-of-the-glacier.html