SHELF-FACIES MICROFOSSILS FROM THE ULUKSAN GROUP (PROTEROZOIC BYLOT SUPERGROUP), BAFFIN ISLAND, CANADA

Coccoid and filamentous microfossils in the Borden Rift Basin on northwestern Baffin Island and western Bylot Island are reported from 14 localities at six general stratigraphic levels in the Society Cliffs Formation, and one in the Victor Bay Formation. At least seven of 12 fossiliferous Society Cliffs samples, and one of two Victor Bay samples, are from cherty dolostones formed in shallow restricted, peritidal evaporitic environments. The remaining six fossiliferous samples accumulated in somewhat deeper, less restricted waters. The assemblage is preserved in black chert nodules and layers and comprises 30 taxa, including the filamentous forms Archaeotrichion? sp., Tenuofilum septatum, Eomycetopsis robusta, Siphonophycus inornatum, S. kestron, Rhicnonema antiquum. Brachypleganon sp., Eomicrocoleus sp., Uluksanella baffinensis n. gen. and sp., Talakania? sp., the coccoid taxa Eosynechococcus medius. E. grandis, Archaeoellipsoides obesus, Sphaerophycus parvum, S. medium, Myxococcoides minor, M. grandis, Melasmatosphaera spp., Phanerosphaerops capitaneus, Palaeoanacystis sp., Tetraphycus hebeiensis, Eogloeocapsa bella, Gloeodiniopsis magna, G sp. 1, G. mikros, Polybessurus bipartitus, Cymatiosphaera? sp., the fusiform Eupoikilofusa? sp., and rare specimens of two unidentified and problematic taxa.