Abstract

Middle Pennsylvanian, Atokan and Desmoinesian, crinoids and echinoids are described from the Belden and Minturn Formations of the Central Colorado Trough. The echinoderms from the Minturn Formation were living in an active intermontane trough setting. They are found in two environments, on the flanks of phylloid algal reefs and in patches on abandoned delta lobes on the gently sloping substrate. Faunas are dominated by cromyocrinids and are similar to stable platform Terrigineous Facies Belt faunas of the Midcontinent. New species described are Dicromyocrinus beldenesis, Neoprotencrinus rockensis, and Sciadiocrinus wipsorum, Goleocrinus, and the columnal genera Blothronagma, Cyclocaudex, and Platyplateium are reported for the first time from the Minturn Formation. The columnal taxa Blothronagma cinctutum and Floricyclus angustimargo are believed to be cromyocrinids. B. cinctutum may be synonymous with Synarmocrinus molasensis, and Floricyclus angustimargo may be synonymous with Ulocrinus rockymontanus.

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