282 G. M. DAWSON ON THE SUPEKETCIAL GEOLOGY OE 



those of the Queen -Charlotte Islands. Similar erratics appear to 

 characterize in greater or less abundance the whole of the low 

 country above described, but are not found about the heads of the 

 south-western extremities of Masset Inlet. 



It has previously been shown that at the time when the Strait-of- 

 Georgia glacier began to diminish the sea must have stood consider- 

 ably higher in relation to the land than at present, and the glaciated 

 rock surfaces about Victoria and Nanaimo no sooner appeared from 

 beneath the glaciers than they were covered by deposits holding 

 marine shells. Such must have been the state of affairs also in the 

 Queen-Charlotte Islands ; and to this time are doubtless to be referred 

 the clay and sand deposits of the low north-eastern part of Graham 

 Island above described. The material of these must have been sup- 

 plied from the glaciers of the islands themselves, but added to also (as 

 the nature of the boulders proves) by the debris borne on floating ice 

 from the larger glaciers of the mainland, the sea levelling and 

 spreading abroad the material, and preventing the formation of any 

 well-marked terminal moraines by the island glaciers. The rocky 

 beds of the fiords and Masset-Inlet expansions must have been shaped 

 to some extent by the ice ; but the absence of drift material from their 

 areas, and especially of the erratics derived from the mainland, are, 

 with their situation, good reasons for supposing that they mark the 

 regions last covered by glacier-ice, and from which it eventually re- 

 treated Avith some rapidity, leaving the hollows formerly occupied 

 by it to become first inlets, and then, with increasing elevation, in 

 some instances lakes. 



The exceptional case which seems to show the impingement on the 

 Queen-Charlotte Islands of ice not produced on them was found on 

 the north coast on the little islands lying outside the entrance to 

 Masset Inlet ; but it is probable that similar traces might be found 

 by search in additional localities in this vicinity. "Wider exposures 

 of basalt a few feet above high-water mark here show very heavy 

 though somewhat worn glaciation in a direction S. 10° E., or JST. 

 10° W., but probably the former. The depth and parallelism of the 

 grooving would appear to show that it is glacier work. The moun- 

 tainous axis of the islands in this their northern part does not ex- 

 ceed in height about 1300 feet, and where nearest is about 15 

 miles from the locality, while the direction of the marking is not 

 that which would be followed by ice descending from the mountains 

 under any circumstances, being more nearly parallel to than radiant 

 from them. It is, however, just that which ice-masses floating up 

 or down the strait separating the islands from the mainland must 

 have taken, or glacier-ice pushing southward from the long fiords 

 of the Prince of Wales group in Southern Alaska, sixty miles 

 distant. It may, I believe, be attributed with greatest probability 

 to the last-named agent ; and in view of the great extension which 

 the glaciers of other parts of the coast must at one time have had, 

 that required for the Prince of Wales group and adjacent channels 

 does not appear excessive. 



