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:
“Under that rock that holds
the first swift kiss
of the spring-sun’s white, incandescent breath,
I’d seek
you flowers.”
—Hilda Doolittle (1886–1961)