Is this what Pennsylvania looked like 20,000 years ago?
It is a reasonable estimation! Actually, in Northeastern PA, even the
hilltops would probably not have risen above the ice surface. The summit
of our highest peak, Elk Mountain in Susquehanna County, is currently at an
elevation of 2680 feet, although it is likely that the glacier scraped off some
unknown amount of material from the top.
As the the glacier retreated, the terminus likely
looked something like the photo below (taken in Alaska). Notice the
dirty ice surface, laden with sand, silt, gravel and boulders. Not
easily seen in the foreground of the photo are streams carrying
these sediments and depositing them as an outwash plain.
