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:
“The forest waves, the morning breaks,
The pastures sleep, ripple the lakes,
Leaves twinkle, flowers like persons be
And life pulsates in rock or tree.”
—Ralph Waldo Emerson (1803–1882)