SUPERFICIAL aEOLOGY OF BRITISH COLUMBIA. 117 



the direction of greater water-agency in its preparation. The stones 

 are rounded and water worn as a rule, heavily glaciated in a few 

 instances, aud mixed with large angular fragments only when these 

 have been abundantly produced by some hill or cliff near at hand. 

 There is also much evidence, especially about Tatla Lake, the Mazco 

 watershed, and on the Nechacco, tending to prove that the gra- 

 dually retreating glaciers piled up some, at least, of these gravelly 

 moraines in water, which was decreasing in depth at the same time 

 with the diminution of the supply of ice. This evidence is chiefly 

 derived from series of flat- topped or water-wasted moraines in 

 .such localities and so arranged as entirely to preclude their being re- 

 ferred to esker ridges. 



4. Mode of Glaciation akd Formation - of the Superficial Deposits. 



In the foregoing I have endeavoured to give a short account 

 of the glacial phenomena and superficial deposits of British Columbia, 

 so far as I have examined them, entering into some detail in a few 

 important and typical cases only, with the view of bringing the 

 facts as they occur, in this hitherto little-known region, to the 

 notice of geologists. Some uncertainty has been expressed as to 

 the action on a large scale of glacial ice on the north-west coast 

 of America, which may now, I hope, be removed, at least so far 

 as regards British Columbia. 



Professor Whitney, in the ' Proceedings of the Academy of 

 Natural Sciences of California,' 1868, says that there is no evidence 

 in California of a general glacial epoch, such as that which affected 

 the Eastern States. He extends this conclusion to Nevada and 

 Oregon, and, following information received from Messrs. Ash- 

 burner and Dall, further remarks that no evidence of northern 

 drift has been detected even so far north as British Columbia and 

 Alaska. Professor Dana, in the last edition of his ' Manual,' quotes 

 "Whitney's statement of the absence of northern drift, at least as 

 far north as Oregon, but alludes to the grooving on Yancouver 

 Island as possibly indicating general glaciation there. Professor 

 Le Conte, however, speaks of northern drift near the Columbia 

 river, east of the Cascade range * ; while Gibbs writes of the 

 country in the vicinity of Pugeb Sound, somewhat further north, 

 that it is "one vast mass of modified drift "t, which he further 

 asserts to have, at least in part, a northern origin, on account of the 

 nature of the erratics. These must have been deposited in con- 

 nexion with the southward extension of the Strait-of-Georgia 

 glacier, or by floating ice after its retreat. 



Dr. E. Brown, in a paper " On the supposed Absence of Drift on 

 the Pacific Slope " J, combats the statements of Whitney and others, 

 quoting especially Mr. Bauerman's observations on the coast- and 



* Am. Journ. Sci. and Arts, March and April, 1874. 



t Journ. Am. Greol. Soc. 1874. 



\ Am. Journ. Sci. and Arts, 1870, p. 318. 



