SPONGES FROM THE PARK CITY FORMATION (PERMIAN) OF WYOMING

A new small twiglike anthaspidellid sponge, Virgaspongiella ramosa new genus and species, and an incrusting lithistid sponge have been recovered from silicified residues of etched limestone blocks from the Middle Permian Franson Member of the Park City Formation in western Wyoming. Virgaspongiella n. gen. has a skeleton of upwardly and outwardly divergent trabs formed of merged tips of runglike dendroclone spicules in ladderlike series. One to a few oxeas function as coring spicules in the trabs and project as fine spines from the dermal surface, and other monaxial spicules project from pores of the canals. The incrusting sponge, Incrustatospongia superficiala new genus and species, forms a distinct, thin, uniform lithistid skeletal layer, composed largely of X-shaped dendroclones, incrusted on both the inner and outer surfaces of productoid brachiopod valves. Separated monaxial spicules locally protrude from the sponge's dermal surface apparently as spinose defensive elements.