SILURIAN. 265 



beneath the sea. The general appearance of the rocks is sunilar to the Dudley limestone and 

 would strike even an observer who was not a geologist. This resemblance to the Upper Silurian 

 beds extends to the structure of the rocks on a large scale. Alternations of hard limestone 

 and soft shale, so characteristic of the Upper Silurian beds of England and America, arranged 

 ia horizontal layers, give to the cliffs around Port Leopold (northeast part of North Somerset) 

 the peculiar appearance which has been described by different polar navigators as "buttress- 

 like," "castellated;" this appearance is produced by the unequal weathering of the cliflE, which 

 causes the hard limestone to stand out in bands. 



A few fossils procured by Hall on the west shore of Kennedy Channel, at Cape 

 Leidy, Cape Frazer, and other points, were examined by Meek,^^* who reported 

 12 species and commented: 



From the foregoing list, it is believed that geologists will agree that the rocks at this 

 highest northern locality at which fossils have ever been collected belong to the Upper Silurian 

 era. The most remarkable fact, however, is that they are nearly all very closely allied to and 

 some of them apparently in all respects undistinguishable from species found in the CatskUI 

 shaly limestone of the New York Lower Helderberg group. 



Authorities for the distribution of Silurian strata throughout the Arctic region 

 are given by Dawson^"® in his detailed account of the scattered data gleaned by 

 him from the writings of many explorers. The localities noted are named below. 

 Dawson also gives a list of localities at which, fossils ha'-^e been obtained. 



P-Q 16-17 Southampton Island. 



Q 18-19 Baffin Land. 



R 10 Cape Parry; Baring or Banks Land. 



R 14-15j King William Land and Boothia Peninsula. 



R 17 Melville Peninsula. 



R-S 11-13 Mainland Coast, Wollaston and Victoria lands. 



. R-S 14 Prince of Wales Island. 



R-S 15-16 Gulf of Boothia. 



S 15 North Somerset. 



Jones,*""' Salter,**^^ and Schuchert"^ may also be consulted. 



Low''"'* describes an area of Ordovician and Silurian limestones covering all 

 but the northeast coast of Southampton Island, most of Coats Island, and all of 

 Mansfield Island and reappearing on Akpatok Island, in Ungava Bay, though not 

 seen on the intervening southern shore of Hudson Strait. The fossils from the 

 south shore of Southampton Island constitute " a fauna closely resembling that of 

 the Lake Winnipeg basin, and extend over a period from the Galena-Trenton to 

 the Guelph and Niagara." 



a 3. SEWARD PENINSULA. 



The Nome group of Seward Peninsula comprises mica schists and probably 

 three massive limestones, which, according to P. S. Smith/'*'' range in age from 

 Cambrian to probably post-Ordovician. The Port Clarence limestone is the oldest 

 division of the Nome group which is known to contain fossils. The faunas of this 

 limestone have been listed by Kindle, ^"^ who states " that a magnesian limestone on 

 Fish River yielded a heavy-shelled lamellibranch comparable with Megalomus 

 canadensis and identical with a species which occurs in the limestone of late Silurian 

 age at Glacier Bay and at Freshwater Bay in southeastern Alaska. (See p. 262.) 



o Personal communication, January, 1910. 



