Buffalo sandstone (previously Upper Mahoning sandstone) underlies Pine Creek limestone and is sometimes separated from underlying Brush Creek limestone by a thin layer of shale. Formation attains maximum development along Buffalo Creek, in Buffalo Twp, Butler Co., PA. Thickness ranges from 60 to 80 ft. Unit was included in the Mahoning sandstone of First Survey but because there is a massive sandstone coming below this, to which term Mahoning has always been applied, it is clear that one or the other should have a distinct name. The two rocks are always distinct, and never merge into one mass. Both sandstones occur on Mahoning Creek. The name Mahoning is here restricted to the lower sandstone.

Source: GNU records (USGS DDS-6; Reston GNULEX).