Upper Permian (Wordian) fusulinaceans from the Cache Creek Terrane, northern British Columbia

Abstract

Fusulinaceans from the Horsefeed Formation, the youngest stratigraphic unit within the allochthonous Cache Creek Terrane southeast of Atlin, include abundant Colania columbiana (Dawson) and Schwagerina? atlinensis Ross, as well as rare representatives of Rauserella sp. and Reichelina? sp. They occur with 13 Upper Permian (Wordian) ammonoid species, including several species of Waagenoceras that are also known from Wordian strata in Mexico and Texas. Colania columbiana was first recorded from strata at Marble Canyon within the Cache Creek Terrane in southern British Columbia by G.M. Dawson in 1879. It was identified then as Loftusia, a non-fusulinacean agglutinated foraminifer, but in the last 60 years it has been assigned to a number of Permian fusulinacean genera, including Neoschwagerina Yabe, Yabeina Deprat, and Lepidolina Lee. Colania is quite distinct from all these genera in characteristics of the shell wall. All but one species of Colania around the world are confined to strata of Wordian or equivalent age; in China, Colania douvillei (Ozawa) extends upwards into strata slightly younger than Wordian, that is, early Capitanian age. A Wordian age appears certain for Colania columbiana from British Columbia, on the basis of evolutionary development and associated ammonoids.