MIDDLE PENNSYLVANIAN, LATE ATOKAN EARLY DESMOINESIAN ECHINODERMS FROMAN INTERMONTANE BASIN, THE CENTRAL COLORADO TROUGH

Middle Pennsylvanian, Atokan and Desmoinesian, crinoids and echinoids are described from the Belden and Minturn Formations of the Central Co lorado Trough. The echinoderms from the Minturn Formation were living in an active intermontane trough setting. They are found in two enviro nments, on the flanks of phylloid algal reefs and in patches on abando ned delta lobes on the gently sloping substrate. Faunas are dominated by cromyocrinids and are similar to stable platform Terrigineous Facie s Belt faunas of the Midcontinent. New species described are Dicromyoc rinus beldenensis, Neoprotencrinus rockensis, and Sciadiocrinus wipsor um. Goleocrinus, and the columnal genera Blothronagma, Cyclocaudex and Platyplateium are reported for the first time from the Minturn Format ion. The columnal taxa Blothronagma cinctutum and Floricyclus angustim argo are believed to be cromyocrinids. B. cinctutum may be synonomous with Synarmocrinus molasensis, and Floricyclus angustimargo may be syn onymous with Ulocrinus rockymontanus.