BIOSTRATIGRAPHIC SIGNIFICANCE OF LOWER MISSISSIPPIAN AMMONOIDS FROM THE PRICE FORMATION IN WEST VIRGINIA AND VIRGINIA

The Price Formation in West Virginia and southwestern Virginia preserves a succession of shallow marine clastic rocks deposited along the eastern flank of the Appalachian Basin associated with the Sunbury Shale transgression. At Marlinton, Pocahontas County, West Virginia, the Price is separated from the underlying Chemung Formation by an unconformity and shares a conformable contact with the overlying Maccrady Formation of Osagean age. Here, the Price is divided into four members, in ascending order: The Cloyd Conglomerate and Riddlesburg Shale Members, which are equivalent to the Berea Sandstone and the Sunbury Shale of the central and western part of the basin, respectively, followed by the Rockwell Member and undifferentiated upper Price.

Whereas Lower Mississippian ammonoid faunas are well known from the southern and west-central part of the Appalachian Basin (Ohio, Kentucky and Alabama), only two species have been reported from the Lower Mississippian interval in the Virginias. This report documents the occurrence of the ammonoids Xinjiangites medius (Miller and Collinson, 1951) and Protocanites lyoni (Meek and Worthen, 1860) from the Price Formation in West Virginia and Virginia, respectively. X. medius is an important biostratigraphic marker and is restricted to the latest Kinderhookian with the holotype occurring in the Northview Formation at Kings Butte, southwestern Missouri, which falls into the isosticha – Upper crenulata conodont zone of Lane and Brenckle (2005). X. medius occurs above the Rockwell Member at Marlinton in the youngest marine deposits in the undifferentiated upper Price. P. lyoni is known to span the Kinderhookian – Osagean boundary. Miller (1936) reported its occurrence from the lower Price at Richlands, Virginia, 52 km south of the Marlinton section, in association with the brachiopods Punctospirifer depressus (Herrick, 1888) and Avonia rushvillensis (Herrick, 1888), both of which also occur in the Early Osagean Logan Formation of Ohio. The occurrence of P. lyoni further south and stratigraphically lower than that of X. medius offers supplementary support of the north to south time transgressive nature of Price deposition reported by Kammer and Bjerstedt (1986), Carter and Kammer (1990) and Matchen and Kammer (1994).