Large specimen of Arborispongia with algae and Leptadesma sp. bivalves. Benthic assemblage. Extensive bioherms of this arborescent sponge occur at the Bear Gulch bay mouth (Rigby 1985).

Arborispongia with Leptadesma sp. bivalve.

Sponge, 100 mm across.

Orbiculoid brachiopod, 13 mm.

Anthracoceras sp, 32 mm showing preservation of mandibles.

Orthocone cephalopod, 128 mm long. Traces of soft parts are visible in the body chamber.

Paraconularia sp., 65 mm.

Nematode worm with filamentous algae. Algal assemblage.

Paleolimulus longispinus, 60 mm, with well preserved limbs in micrite.

Aenigmacaris cornigerum, a complete 10 cm eumalacostracan shrimp.

Bairdops beargulchensis Schram & Horner, 50 mm complete in micrite.

Tyrannophontes theridion, 38 mm.

Perimecturus rapax, 64 mm crustacean.

A finely preserved 11 mm Halicyne montanaensis, one of a group of five.

Dithyrocaris rolfei Schram & Horner 1978, a complete 7 cm phyllocarid. Heath Shale Formation. Bear Gulch Limestone. Bear Gulch, Fergus County, Montana, USA.

Acantonescus cracens, 142 mm palaeoniscoid fish.