The Neruokpuk Formation of the Barn Mountains and Driftwood Hills, Northern Yukon; its Age and Graptolite Fauna
The pre-Carboniferous racks of the Bam Mountains consist of a very thick, highly deformed and dislocated sequence of mildly metamorphosed elastics and carbonates assignable to the Neruokpuk Formation. The Driftwood Hills, for the most part, are composed of dark shales possibly assignable to the Neruokpuk Formation. Graptolites collected from a number of thin shale beds in the two areas are correlative with the Arenigian, Llanvirnian, Ashgillian, ?Llandoverian, Ludlovian, and Siegenian or Emsian Stages. It is suggested that complete, or nearly complete Ordovician and Silurian sedimentary sequences are present, and that these sediments represent geosynclinal equivalents of cratonic sediments to the south and southwest.