Only brief mention of Ordovician and Silurian fossils from Somerset and Prince of Wales islands has been made in past geological reports. A more comprehensive list of fossils collected from the two lowermost Paleozoic formations (the Lang River and Allen Bay) is presented. Three distinct faunal groups are present in these two formations, a Lower Ordovician, an Upper Ordovician (“arctic” Ordovician) and a Silurian fauna. The rich and diverse “arctic” Ordovician fauna is comparable to the Stony Mountain fauna of Manitoba. The Silurian fossils are probably Niagaran in age (Middle Silurian).