506 THE GLACIAL LAKE ACxASSIZ. 



Griunell Land it was from 1,000 to 2,000 feet, as shown by raised beach 

 deposits containing marine shells.' 



That the land northward from Boston was so mnch lower while the 

 ice-sheet was being melted away is proved by the occun-ence of fossil 

 shells of far northern range, including Yoldia (Leda) ardica Gray, now 

 fonud living only in arctic seas where they receive mtiddy streams from 

 existing glaciers and from the Greenland ice-sheet. This species is plentiful 

 in the stratified clays resting on the till in the basin of James Bay, in the 

 St. Lawrence Valley, and in New Brunswick and Maine, extending south to 

 Portsmouth, N. H. 



Scantier but yet conclusive proofs of the depression of British Colum- 

 bia under the ice load are found in the valley of the Fraser River and on 

 the Pacific coast, in Vancouver Island and the Queen Charlotte Islands. 

 Lamplugh has observed recent marine shells in a railway cutting on the 

 west bank of the Harrison River, near its junction with the Fraser, at an 

 elevation not less than 100 feet above the sea." At New Westminster, on 

 the Frazer, near its mouth, raised beaches inclosing fragments of marine 

 shells are reported bj- Bauerman about 30 feet above the river.^ Fossilif- 

 erous marine deposits found in the vicinity of Victoria and Nanaimo, in the 

 southeast part of Vancouver Island, at small elevations abo^'e the sea, are 

 believed by Dr. G. M. Dawson to have been formed at or near the wasting 

 edge of the ice-sheet;* and near the middle of the northeast side of this 

 island two distinct deposits of till occur, with intervening beds of loess-like 

 silts, from which this author infers two times of glaciation, separated by an 

 interval during which the land was submerged from 100 to 200 feet.^ 

 Again, in the northeast part of the Queen Charlotte Islands Dr. Dawson 



'Quart. Jonr. Geol. Soc, Vol. XXXIV, 1878, pp. 66, 566. Geol. Magazine (3), Vol. I, 1884, p. 522. 

 A. W. Greely, Report on the U. S. Expedition to Lady Franklin Bay, Griunell Land, Vol. II, 1888, p. 57. 



'Quart. Jour. Geol. Soc, Vol. XLII. 1886, pp. 284, 285. 



^Gi'ol. and Nat. Hist. Survey of Can.ada, Report of Progress for 1882-83-84, p. 33 B. 



■"Geol. and Nat. Hist. Survey of Canada, Annual Report, new series, Vol. II, for 1886, p. 99 B ; Quart. 

 .Jour. Geol. Soc., Vol. XXXIV, 1878, jip. 97, 98, aud Vol. XXXVII, 1881, p. 279. Compare .also Mr. G. W. 

 LampluKh's olj.servations of glacial shell beds at Esquimault, near Victoria, Quart. .lour. Geol. Soc, 

 Vol. XLH, 1886, pp. 276-284. 



■■^Geol. and Nat. Hist. Survey of Canada, Annual Report, nevr series, Vol. II, p. 105 B. 



