C. Schuchert — Notes on Arctic Paleozoic Fossils. 469 



2. Ordovician. A black, fine-grained, thin-bedded limestone. 



Basilicus canadensis (Chapman). A large tail of this very- 

 characteristic trilobite is present. 



This horizon is clearly in the lower part of the Collingwood 

 as developed at Collingwood, Ontario, a formation of wide 

 occurrence in that province. It is of wide distribution in 

 southern Baffin Island and will probably be found generally 

 throughout the Arctic region where Ordovician strata are 

 exposed. It may also occur on Akpatok Island. 



3. Lower Devonian. A light-colored, thin-bedded limestone 



replete with fossils. The following are the species: 



Zaphrentis roerneri Edwards and Haime. Rare. 



Stropheodonta varistriata (Conrad). The specimens are 

 very small here. 



Strophonella like euglypha (Dalman) of the Silurian. 



Leptcenisca concava (Hall). This very characteristic thin- 

 shelled brachiopod is present in many fragments. It 

 attains a larger growth here than in New York. The 

 species is now known to occur almost everywhere where 

 the Helderbergian is exposed. 



Gypidula (Sieberella) pseudogaleata (Hall) ?. Ami has given 

 this the name of Clorinda lowi (nom. nud.). 



Gypidula [Sieberella) coey?hansensis chidleyensis Ami. 

 Specimens of this form make up a slab of limestone, and 

 differ from the New York species in being more decidedly 

 plicated. 



Pleurotomaria labrosa Hall ?. The revolving and growth 

 lines are finer in this specimen than in New York examples. 



This geologic horizon is clearly Helderbergian and agrees 

 remarkably well with the uppermost Coeymans division as 

 developed in the United States. G. pseudogaleata in New 

 York is, however, restricted to the uppermost Helderbergian 

 (Becraft), but at Dalhousie, New Brunswick, it occurs at a 

 lower level and is there associated with Leptcenisca concava 

 and other New Scotland fossils. 



Frobisher Bay Collections of Hall. 



A part of the collections made by Mr. C. F. Hall of New 

 London, Connecticut, on his first expedition to the Arctic 

 regions in 1860-1862 is now in the museum of Amherst Col- 

 lege. This material was originally described by Professor 

 Emerson and is that which was loaned the writer for the 

 present study. 



