of material for the manufacture of brick and other clay products, as well as a local building stone. References See also Geology of Pennsylvania Silurian System of North America Claystone Sandstone formations of the United States Shale formations of the United States Cliff-formers Silurian United States Silurian Maryland Silurian geology of New York (state) Silurian geology of Pennsylvania Silurian geology of Virginia Silurian West Virginia Geologic formations of Maryland Geologic formations of New Jersey Geologic formations of New York (state) Geologic formations of Pennsylvania Geologic formations of West Virginia Silurian southern paleotemperate deposits Gorstian Ludfordian