MacDEM produced great DEM files. I wanted to adjust these to see how the topography of Western NY looked while all those lakes were making beaches everywhere. The best I could come up with was Fairchild's 1918 map.
First with REALBasic, and then with GRASS and Gdalwarp, I managed to tilt the DEMs back to remove this uplift. The numbers I arrived at were:
to the E 50 ft in 60 miles = 0.0001570
to the N 100 ft in 50 miles = 0.0003788
This is equivalent to a strike and dip of
N 67.5°W, 0.023° NE
Hinge was set at 42°N, 78°W
Here are links to maps with the tilt removed (you may want to use your Download button):