32 PROCEEDINGS OF THE SAIXT LOUIS MEETIXG 



Assistant Geologist on the Geo-logical Survey of Canada and, in 1914, 

 was appointed to the senior rank of a regular field officer. All of his 

 geological work was done in his chosen field of British Colmnbia. 



Drysdale's intense devotion to the geology of this field is reflected in 

 the character and importance of the reports that he produced in a com- 

 paratively short time. In his three memoirs on the Franklin, Rossland, 

 and Ymir camps, respectively, clear and graphic descriptions of the com- 

 plex succession of events that produced the existing geological relations 

 within these areas are illustrated by cleverly executed diagrams, sketches, 

 and sections. Of especial interest also are his detailed descriptions of the 

 petrographical character and relative ages of the igneous rocks in these 

 highly disturbed areas. 



But it is chiefly in connection with his application of geology to the 

 solution of problems relating to the ore deposits of these mining districts 

 that Drysdale made his reputation. Since its discovery in 1890 to the 

 close of 1916, the Eossland Mining Camp has produced 5,282,242 tons 

 of ore, with gold, copper, and silver contents worth $69,678,670 — a pro- 

 duction which exceeds in value that of any other lode mining camp in 

 British Columbia. It is merely because of the exceptional economic im- 

 portance of the area involved that Drysdale's memoir on Rossland has 

 attracted more attention than his memoirs dealing with the Franklin 

 and A'mir Mining cam23s. 



In 1894 and 1896, a reconnaissance geological survey of the Rossland 

 district was made by Mr. R. G. McConnell, who is now the Deputy Min- 

 ister of Mines in Canada. In 1905 and 1906, this area was studied in 

 more detail by Mr. R. W. Brock and Dr. G. A. Young and, in 1906, a 

 brief preliminary report by Mr. Brock was published. In Xovember, 

 1907, Mr. Brock assumed the duties of Director of the Geological Survey 

 of Canada, and although a detailed geological map of Rossland appeared 

 in 1909, he was unable to find time to prepare his final report. The 

 geological work in this area was not completed until, in 1913 and 1914, 

 Drysdale made a very thorough and detailed study both of the surface 

 and underground in the mines and, making free use of the data collected 

 by Brock and Young, produced one of the most valuable of the memoirs 

 that have been published by the Geological Survey of Canada. 



During and since the Carboniferous period, the Rossland district has 

 repeatedly been invaded by ascending magmas which at times were asso- 

 ciated with the development of volcanic activity. The results of his ob- 

 servations as to sequence of igneous intrusions, detailed petrographical 

 distinctions between the various rock types and phases of the same type, 

 the development of fault and fissure systems of different ages, and as to 



