ABSTRACT
The geological formations of coastal Maryland and Virginia, in reality the seafloors deposited within the Salisbury and Albemarle basins, are placed together in the Chesapeake Group (Clark, 1904:29-30). Within this group, eight formations are recognized: the Oligocene-Miocene Old Church Formation, the Miocene Calvert, Choptank, St. Mary’s, and Eastover Formations, the Pliocene Yorktown and Chowan River Formations, and the early Pleistocene James City Formation (Figure 2.1 and Figure 2.2). All eight formations have similar lithologies, being composed of varying amounts of clay, mud, and sand mixed with thick beds of fossil shells. The molluscan fossil component contributes a high carbonate concentration to these formations, setting aside the Chesapeake Group from the other geological units within the Atlantic Coastal Plain. In this book, only the four Miocene formations of the Chesapeake Group will be discussed.
