THE GEOLOGY OF THE ARCTIC COASTS. 557 



The dip of these rocks is very high and often vertical, and they 

 are traversed by true slaty cleavage, the planes of which are some- 

 times horizontal, much more often inclined at high angles, their 

 strike being N.N.E. Associated with these slates are impure lime- 

 stones frequently ^traversed by veins of quartz and chert. Further 

 to the north, commencing in latitude 82° 33', the above-mentioned 

 rocks give place to a vast series of quartzites and grits, rising to 

 elevations of 2000 and 3000 feet on either side of Westward-Ho 

 valley, through which passes an anticlinal axis which carries the rocks 

 down below the Carboniferous Limestone of Feilden peninsula. 



Dr. Conybeare was perhaps the first to recognize (in 1832) the pre- 

 sence of Upper Silurian fossils in collections brought from the Arctic 

 archipelago ; and the subsequent study of the late Mr. Salter and 

 Dr. Haughton supported this identification, and referred the horizon 

 to that of the Niagara and Onondaga groups, the equivalents of our 

 Wenlock and Dudley. These limestones occupy the south of North 

 Devon and nearly all the islands south of Melville and Lancaster 

 Sounds, includiug the south of Banks's Land, Prince Albert's Land, 

 Prince of Wales's Land, King William's Land, North Somerset, 

 Boothia Felix, &c. 



Upper Silurian fossils occurring in a conglomerate resting on the 

 Laurentian rocks of the Hudson-Bay Territory, observed by Sir John 

 Richardson, caused Sir Eoderick Murchison and others to believe 

 that the entire Polar area was dry land during the whole time -y 

 occupied by the deposition of the Lower Silurian rocks elsewhere. 



But the specimens brought by the late Expedition, and identified 

 by Mr. Etheridge, prove that this is not the case, and that the Lower 

 and Upper Silurians are both present on the shores of Kennedy 

 Channel. 



From the occurrence of Lower Silurian forms among the species 

 collected by M'Clintock in cream-coloured dolomite around the mag- 

 netic pole, on the western coast of Boothia, in King William's Island, 

 and Prince of Wales's Land, there would appear to be little doubt 

 that these dolomites represent the whole of the Silurian, and possibly 

 a part of the Devonian. 



The base of the Silurians consists of finely stratified Red Sandstone 

 and slate in North Somerset, where it is overlain by ferruginous 

 limestones with quartz-grains, underlying pale cream-coloured lime- 

 stone dipping 5° to N.N.W. 



The coarse basement beds are seen on Cape Warrender and 

 Wolstenholm Sound, and to this horizon the basement beds of the 

 Silurians of the south coast of Bache Island may be referred ; these 

 rest on syenitic and granitoid rocks, and are overlain by mural cliffs 

 of limestone, rising to a height of more than 1000 feet, dipping 

 gently to N.N.W. as far as Victoria Head, where a landing was 

 effected and a small collection of fossils obtained. 



The northern shore of Bache Island presents a very straight line 

 of mural cliff composed of this formation, coinciding in direction 

 with its strike. 



Norman-Lockyer Island (lat. 79° 25' N.) lies at the mouth of 



