556 H. W. FEILDEN AND C. E. BE RANCE ON 



35. Geology of the Coasts of the Arctic Lands visited by the late 

 British Expedition under Captain Sir George Nares, R.N., 

 K.C.B., F.B.S. By Captain H. W. Feilden, F.G.S., and C. E. De 

 Eance, Esq., F.G.S., Assoc. Inst. C.E. (Bead April 17, 1878.) 



[Plate XXIV.] 



The Lanrentian rocks described by Sir William Logan occupy an 

 area of 200,000 square miles in Canada, and attain a thickness of 

 40,000 feet in two series, the one unconformable to the other, 

 and, stretching northwards, form the fundamental rocks of the Polar 

 area. 



Fringing the North-American coast they plunge beneath the 

 Silurians and Carboniferous rocks of the Parry archipelago, reap- 

 pear in the gneiss cliffs of Cape Isabella, form the entire coast of Elles- 

 mere Land, rising to heights of 2000 feet, and underlie the Miocene 

 rocks of Port Foulke, the Miocene and Cretaceous rocks of Disco 

 Island, Noursoak peninsula, and the Oolites of Pendulum Island, in 

 East Greenland. 



Cape-Bawson Beds. — The vast series of ancient rocks occupying the 

 country between ScoresbyBay and Cape Cresswell, in lat. 82° 40' IS"., 

 appear to represent in time the Huronian epoch of North America; for 

 they are evidently newer than the gneiss and crystalline rocks of the 

 Laurentian, and older than the f ossiliferous Silurians. In Nova Scotia 

 Prof. Yule Hind has shown that the Laurentian gneiss is uncon- 

 formably overlain by micaceous schists, waterworn quartz-pebbles, 

 and gneiss-conglomerate, made up of fragments of the ancient rocks 

 beneath, proving the very ancient period to which the metamorphism 

 of the gneiss must be referred ; and he has also shown that these 

 gneissic conglomerates are further overlain by 9000 feet of quartzites, 

 grits, black slates, and thin beds of auriferous quartz, which, in their 

 turn, are probably unconformable with the gneissoid conglomerates 

 beneath. The black slates, often gold-bearing, attain a thickness 

 in Nova Scotia of 3000 feet ; and from the analogy of their manner 

 of occurrence, close lithological similarity, and the fact of their 

 both preceding the incoming of the Silurian fauna, there would ap- 

 pear to be a strong probability that the Huronians of Nova Scotia 

 are the equivalents in time with the rocks that constitute the north- 

 eastern portion of Grinnell Land, which we have designated the Cape- 

 Raivsonbeds, from the locality where they are conspicuously displayed. 



The strata of Cape Bawson are thrown into a series of sharp 

 anticlinal and synclinal folds, the axes or strike of which range about 

 W.S.W., and abruptly terminate in the sea-cliffs of Black Cape, 

 Cape Union, and other prominent headlands, the enormous masses 

 of jet-black slates forming the very strongest contrast to the 

 foreground of frozen sea and the background of snow-covered 

 slopes — a landscape the appalling desolation of which it would be 

 difficult to find words to paint. 



