The Permian ammonoids of Arctic Canada

America. The present study comprises the description of all specimens secured from Arctic Canada and Alaska; additionally, the two species recorded previously from Greenland are redescribed partly on the basis of a new collection. Cyclolobus kullingi (Frebold) and Medlicottia malmqvisti (Frebold) occur in the uppermost Permian (Dzhulfian) "Martinia-beds" of central East Greenland. In the Queen Elizabeth Islands, Paragastrioceras n. sp. is recorded from a Lower Permian formation on northern Ellesmere Island; Neoshumardites cf. N. sakmarae (Ruzhencev), Paragastrioceras a.ff. P. jossae (de Verneuil) , Uraloceras involutum (Voinova), Uraloceras burtiense (Voinova), and Metalegoceras crenatum n. sp. are associated in the Lower Permian Assistance Formation of southern Ellesmere Island. The type Assistance Formation of Devon Island contains Pseudogastrioceras fortieri Harker and Spirolegoceras harkeri Ruzhencev, forms which are referred to the uppermost Lower Permian but are considered as younger than the ammonoid fauna of the Assistance Formation on Ellesmere Island. The Upper Permian (Guadalupian) of Cameron Island has yielded a single ammonoid, the type of Neogeoceras macnairi n. sp. Unnamed Lower Permian sequences in the Richardson Mountains of the northern Yukon Territory and adjacent areas of Alaska are the source of ammonoids referable to Eoasianites sp., Metalegoceras crenatum n. sp., and Neouddenites caurus n. sp. Neogeoceras sp. occurs in an unnamed Upper Permian stratum of the Richardson Mountains in the northwestern District of Mackenzie. Poorly preserved specimens from the Sadlerochit Formation of northern Alaska are referred doubtfully to Pseudogastrioceras; they are of probable Upper Permian (Guadalupian) age. Syrdenites stoyanowi n. gen., n. sp., a medlicottiin related to the representative from Greenland, is named for a form from the Upper Permian (Dzhulfian) of Soviet Armenia. The Permian ammonoids of Arctic North America constitute an element of the "Boreal Realm". Affinities are with faunas from the Ural Mountains, Siberia, and Australia.