The Somerset Shale Member (Salem Limestone) of Kentucky:
by Don R. Chesnut
The Mississippian-age Somerset Shale Member is generally a highly
fossiliferous shale found at the base of the Salem Limestone. The shale
member was named by Charles Butts in 1922 for outcrops near Somerset,
Pulaski County, Kentucky. Although discontinuous, the Somerset Shale
separates the Warsaw Limestone below and the Salem Limestone above. The
Somerset is found in south-central Kentucky, but equivalent shale beds
may be found in Indiana, Illinois and Tennessee. The Somerset Shale is
age equivalent to the Meramec of the Mid-Continent region of the United
States and mid-Visťan of Europe, most likely the Holkerian of
Britain, the Livian of Belgium and the Tulsky of Russia (Greb and
The Somerset Shale is laterally correlative with the Science
Hill Sandstone which is found in Rockcastle and adjacent counties in
Kentucky. The Science Hill was probably a proximal-subaqueous-deltaic
deposit whereas the Somerset Shale was a more distal deltaic muddy
deposit to the west and south of the sandstone.
More details and history about the Somerset Shale can be found in Feldman (1984, 1987, 1989).
macrofauna from the Somerset Shale include vertebrates, echinoderms,
mollusks, brachiopods, bryozoans, cnidarians, poriferans and arthropods. Most
abundant are the echinoderms, brachiopods and bryozoans. The crinoid Dichocrinus simplex, the blastoid Pentremites conoideus, the brachiopods Cleiothyridina and Composita as well as fenestellid and ramose bryozoans are especially abundant. See the following categories for more information.