BRANCHING HELIOPHYLLUM (DEVONIAN RUGOSE CORALS) FROM NEW-YORK AND OHIO

Solitary species of Heliophyllum are the most common form of the genus but branching and massive colonies do occur, especially in Middle Dev onian strata of eastern North America. Heliophyllum delicatum n. sp. o ffsets laterally and has a dendroid, broad bushy growth form. The spec ies is known only from western and west-central New York and appears t o be limited to the lower part of the Deep Run Shale Member of the Mos cow Formation (middle Givetian); specimens are common within this rest ricted geographic and stratigraphic range. The skeleton of H. delicatu m was poorly designed for the common coral environments of the Devonia n, but seems to have been well adapted to muddy, carbonate-poor condit ions where its thin skeletal elements required less calcium carbonate and its unsupported branches were not subject to vigorous water moveme nt. Heliophyllum stewarti n. sp. is based on a single specimen from th e Tenmile Creek Dolomite (middle Givetian) in northwestern Ohio. The c olony is phaceloid but each branch is an astreoid cluster without wall s between individual corallites. In addition, the apparent protocorall ite is turbinate with a larger diameter than any of the ceratoid offse ts although offset lengths are several times that of the protocorallit e.