No. 1.] DAWSON — GLACIATION OF BRITISH COLUMBIA. 35 



8. The sequence of events in the interior region has been : — 

 glaciation from north to south, with deposit of boulder-clay; for- 

 mation of terraces by lowering of water-surface, accompanied or 

 followed by a warm period ; short advance of glaciers from the 

 mountains contemporaneously with formation of lower terraces ; 

 retreat of glaciers to their present limits. Glaciation of Van- 

 couver Island may have occured duriog both the first and second 

 cold periods, or during the second only. 



9. If the north-to- south glaciation has been produced by 

 glacier-ice, it must have been either («) by the action of a sreat 

 northern ice cap (against which grave difficulties appear), or (i) 

 by the accumulation of ice on the country itself, especially on 

 the mountains to the north. In either case it is probable that 

 the glacier filled the central plateau, and, besides passing south- 

 ward, passed seaward through the gaps and fjords of the Coast 

 Range. The boulder-clay must have been formed along the front 

 of the glacier during its withdrawal, in water, either that of the 

 sea, or of a great lake produced by the blocking by local glaciers 

 of the whole of the valleys leading from tbe plateau, to a depth 

 of over 5000 feet. 



10. If general submergence to over 5000 feet be admitted, 

 the Japan current would flow strongly through Behring's Strait, 

 and over part of Alaska, while arctic ice-laden water, passing 

 south across the region of the great plains, would also enter the 

 central plateau of British Columbia, accounting for the north- 

 to-south glaciation and simultaneous formation of the boulder- 

 clay. 



To these conclusions the facts met with during the continua- 

 tion of the geological work in 1877 and the past summer, enable 

 some very interesting additions to be made, all which tend to 

 show that the opinions previously formed are in the main correct. 



The region examined in 1877 embraced the southern portion 

 of the Interior Plateau, with portions of the Coast and Gold 

 Ranges. Evidence of the north to south glaciation above referred 

 to, were found in a number of additional localities, on the higher 

 parts of the southern portion of the plateau, and traced to a 

 height, on Iron Mountain at the junction of the Rivers Nicola 

 and Coldwater, of 5280 feet. These observations, with those of 

 former years, cover a portion of the Interior Plateau over three 

 hundred miles in length, and show that the ice pressed onward 

 over the southern portion of the plateau to, or even beyond the 



