Geologic Map of Georgia -- Ridge and Valley


Georgia Geologic Survey
1977

David E. Lawton


Ridge and Valley Geologic Map



Ridge and Valley Sedimentary Rocks

(In stratigraphic order)

Pennsylvanian symbol PENNSYLVANIAN ROCKS Includes the sandstone, conglomerate, shale, and coal of the Lookout Plateau.
Mississippian symbol MISSISSIPPIAN ROCKS Includes limestone, shale, and chert with lesser sandstone units.
Devonian symbol DEVONIAN ROCKS Includes sandstone. shale, and chert. Underlain by SILURIAN ROCKS, composed of an iron-rich complex of sandstone, siltstone, and shale. Underlain by ORDOVICIAN ROCKS, including Middle and Late Ordovician shale and limestone.
Cambrian/Ordovician symbol CAMBRIAN AND ORDOVICIAN ROCKS Includes units which transgress the time boundary between the Ordovician and Cambrian Periods; composed of limestone, dolomite, and chert.
Cambrian symbol CAMBRIAN ROCKS Includes those units comprising a group of shale, limestone, and lesser units of dolomite underlain by another group of Cambrian rocks, composed of a thick sequence of shale, siltstone, sandstone, limestone, and dolomite.
Cambrian/PreCambrian symbol CAMBRlAN-preCAMBRIAN ROCKS Includes the sedimentary quartzites of the eastem Ridge and Valley Province.


Map and legend are reproduced from Geologic Map of Georgia, 1977 (1:2,000,000), compiled by David E. Lawton, available from Georgia Geologic Survey.

This map and the larger (1:500,000) 1976 Geologic Map of Georgia were compiled when the ideas of plate tectonics were relatively new and their implications for Georgia geology were not well understood. See reading list for more recent interpretations.