proceedings: geological society 539 



A microscopic study of sulfide ores of copper (illustrated) : L. C. 

 Graton. This paper is presented in full in the Bi-nioyitfily Bulletin of 

 the American Institute of Mining Engineers. 1913. 



The 271st meeting of the Society was held in the Cosmos Club on 

 May 14, 1913. 



Reconnaissance of the Lower Eraser River, B. C. : N. L. Bowen. The 

 speaker examined the region bordering on the Fraser River from Lyt- 

 ton to Vancouver, British Columbia, during the summer of 1912, for the 

 Geological Survey of Canada. The section crosses the Coast-Cascade 

 uplift. The oldest rocks are highly disturbed argillites and quartzites 

 with thin beds of limestone and associated volcanic rocks which are 

 correlated on lithologic grounds with the Cache Creek group of Penn- 

 sylvanian age. With these are infolded a series of banded gray argil- 

 lites which have yielded a single Mesozoic fossil and which are consid- 

 ered probably Jurassic. These latter have formerly been described by 

 G. M. Dawson under the name Boston Bar group and tho he considered 

 them probably Palaeozoic, the name is retained. Both of these earlier 

 series strike, as a rule, northwestward and commonly have high dips. 

 They have been invaded by Upper Jurassic granites which are generally 

 somewhat sheared and in places have become typical gneiss. On the 

 western flank of the Coast Range, near Agassiz and Chilliwack, occurs 

 a sedimentary series which is probably also Jurassic, tho much less 

 metamorphosed than its supposed eastern equivalent (Boston Bar group). 

 The beds have yielded only indefinite Mesozoic fossils. The chief rock 

 types are conglomerate, argillite, usually black, and limestone with a 

 possible basal member of quartz porphyry. The strikes are north- 

 eastward, a rather unusual strike in the Cordillera. 



Lower Cretaceous rocks, characterized by a moderate degree of dis- 

 turbance, occupy a do^vn-faulted belt running roughly parallel to the 

 valleys of Fraser and Anderson rivers. The structure within the belt 

 is synclinal. The rocks are dominantly clastic; arkose, argillite, and 

 conglomerate making up the group, locally termed the Jackass Moun- 

 tain group. Later batholithic rocks, provably Upper Cretaceous, 

 occupy a mde belt near Hope and Agassiz. They differ from the Ju- 

 rassic granites in being fresh and unsheared, and the dominant types 

 are granodiorite, quartz diorite, and diorite with a later alkaline granite 

 probably separated from the other types by a considerable time interval. 

 The Jurassic and the Cretaceous batholiths make up the Coast Batho- 

 lith. The Eocene beds of the Puget group occurring in the lower courses 

 of the Fraser are clearly younger than all the rocks heretofore men- 

 tioned including the later batholiths. They are slightly disturbed and 

 consist, on the whole, of little indurated beds of sandstone, conglomerate, 

 and shale, presumably of estuarine character. The whole region with 

 the exception of the higher peaks was covered with the Cordilleran ice 

 sheet. 



So77ie special features of the glaciation of the Catskill Mountains: H. 

 E. Merwin. Many of the rounded peaks of the Catskills reach heights 



