Rock Formations
See also: List of mapped rock formations in PennsylvaniaPennsylvania has been updating its base geologic map last printed in 1980. New research has shifted the names of several formations and promoted or demoted many different sequences on the stratigraphic chart.
Read more about this topic: Geology Of Pennsylvania
Famous quotes containing the word rock:
“Here is no water but only rock
Rock and no water and the sandy road
The road winding above among the mountains
Which are mountains of rock without water
If there were water we should stop and drink
Amongst the rock one cannot stop or think”
—T.S. (Thomas Stearns)