Fossils from lower part of the Mancos Shale, Disappointment Valley, San Miguel County, Colorado

About 400 fossiliferous segments of drill core from the lower part of the Mancos Shale of Late Cretaceous age were collected by the author during an exploratory drilling program for uranium deposits conducted in 1955 and 1956 by the Geological Survey in the Disappointment Valley area, San Miguel County, Colo. "The samples were submitted to the late J. B. Reeside, Jr., of the Geological Survey for identification. Reeside's identifications are being released in open file in order to make them available to those interested.