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:
“Margaret: Some people have life made for them.
Frank: That’s right, Mrs. Hammond, and some people make it for themselves. It’s about time you took that ton of rock off your shoulders.”
—David Storey (b. 1933)