PRELIMINARY REPORT ON DACRYOCONARIDS IN THE UPPER EIFELIAN BAKOVEN MEMBER OF THE UNION SPRINGS FORMATION

The Bakoven Member of the Union Springs Formation is an upper Eifelian unit of dark gray to black shale, limestone, and calcareous concertions that was deposited in the actively subsiding Appalachian foreland basin during Acadian Tectophase II as the highstand and falling stage systems tracts of T-R Cycle Id. The Union Springs and the overlying Oatka Creek formations constitute the Marcellus subgroup. Traditional faunal lists for the unrestricted Marcellus include only two dacryoconarid species Styliolina fissurella (Hall) and Viriatellina gracilistriata (Hall). Previous examination of James Hall's Marcellus syntypes for the former revelealed that all are undescribed forms of Striatostyliolina, casting doubt on the occurrence of S. fissurella in the Bakoven. A recent study of tha small set of Bakoven samples confirmed the presence of S. fissurella but not V. gracilistirata. Undescribed forms of Homoctenus and Costulatostyliolina also occur in the Bakoven along with at least three froms of Nowakia including N. halihanenis. This observation extends the base of the N. halihanensis zone downward from the lower Givetian Halihan Hill Bed to the approximate base of the Bakoven. it also confirms that, where dacryoconarids are concerned, the Bakoven fauna includes invasive speices for no possible ancestor for H. halihanenis has been observed in the lower to mid Eifelian Onondaga Formation or its equivalents within the Appalachian Basin.