262 Joseph Barrell. 



tion of some degree of ability until I learned that I was 

 indebted to the miners ' nnion which fixed the minimum 

 wage for laborers underground at that figure. The work 

 was interesting and involved difficult problems in the 

 plumbing of crooked shafts, and the measurements of 

 amounts of ore extracted from old workings.' ' These 

 experiences led to his publishing in Mines and Minerals 

 during 1899 and 1900 a series of five papers which he 

 wrote while at Yale studying for the doctor's degree. 

 They have to do with the methods and errors of mine 

 surveying, instrumental errors, methods of keeping 

 stope books, and the choice of survey instruments. The 

 papers abound in mathematics and in diagrams, and 

 thus foreshadow two of Barrell 's future tendencies in 

 geology. 



Regional Geology and Met amor phism. 



During the summer months of 1899, Barrell was field 

 assistant to "W. H. Weed of the U. S. Geological Survey, 

 mapping the ore-bearing formations of the Elkhorn Min- 

 ing district of Montana. This work, Barrell states, was 

 done alone, much of it on horseback, in the mountain- 

 ous region between Butte and Helena. It involved a 

 study of the great successive intrusions of molten rock 

 which in the early Tertiary had broken up the crust, 

 and brought in the wealth of gold, silver, and copper. 

 The first result of these field studies was the publication 

 of the "Geology and Ore Deposits of the Elkhorn Min- 

 ing District," by W. H. Weed, with an "Appendix on 

 the Microscopical Petrography of the District,' ' by 

 Joseph Barrell. 



Having done this field work, Barrell returned to Yale 

 in the autumn of 1899 and made his results the basis 

 of a dissertation for the doctorate. With the guidance 

 of Professor L. V. Pirsson, he made an elaborate petro- 

 graphic study of the rocks, and these results, along with 

 the geology of the Elkhorn area, formed the basis of 

 his dissertation, which is entitled "The Geology of the 

 Elkhorn Mining District." 



As a result of the Elkhorn work, Barrell in his dis- 

 sertation wrote a chapter on "The Physical Effects of 

 Contact Metamorphism. " This is also the title of an 

 article published in this Journal in 1902, and abstracted 

 from the chapter referred to. In this paper Barrell 



