Date of Award

Fall 1985

Document Type


Degree Name

Master of Science (MS)


Ocean & Earth Sciences



Committee Director

Stephen J. Culver

Committee Member

John Repetski

Committee Member

Carl Koch

Call Number for Print

Special Collections LD4331.G4O76


Conodonts collected from two measured sections in the northern Shenandoah Valley of Virginia indicate that locally the Cambrian-Ordovician boundary is within the upper part of the Conococheague Formation and that the Conococheague-Stonehenge formational contact as defined in this study, is diachronous in relation to the boundary. Using the generally accepted definition of the CambrianOrdovician boundary as at the base of the trilobite Missisguoia Zone or within the conodont Hirsutodontus hirsutus Subzone of the Cordylodus proavus Zone, it is found here that the boundary is 230 ft (70 m) below the formational contact at the Narrow Passage Creek section. Several North American Midcontinent Province zonal units are recognized at Narrow Passage Creek, including the Cambrian Proconodontus Zone, the mainly Ordovician Cordylodus proavus Zone, Conodont Fauna B, and Conodont Fauna C. At the section near Timberville, the upper part of the Cordylodus proavus Zone, Conodont Fauna B, and Conodont Fauna Care present. The Conococheague-Stonehenge formational contact is believed to be diachronous in the study area. At Timberville, the formational contact is approximately at the Conodont Fauna B - Fauna C boundary, whereas at Narrow Passage Creek the same contact lies at a much lower level, within the upper part of the Cordylodus proavus Zone.


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