SAMUEL FRANKLIN EMMONS. 835 



SAMUEL FRANKLIN EMMONS (1841-1911) 



Fellow in Class II, Section 1, 1903. 



Samuel Franklin Emmons, one of the most eminent students and 

 investigators of economic geology, was born in Boston, March 29, 

 1841, and died at his home in Washington, March 28, 1911, thus 

 lacking only one day to complete his seventieth year. Since 1867 

 he was connected with the federal scientific surveys, first as a member 

 of the Geological Exploration of the Fortieth Parallel under Clarence 

 King and later, since 1879, as a geologist of the U. S. Geological 

 Survey. For both organizations he performed most important sci- 

 entific work both of a purely geological and practical nature and his 

 name will always be prominently associated with the development 

 of geology in America. 



Emmons obtained his degree of Bachelor of Arts at Harvard and 

 afterward studied three years at Ecole des Mines in Paris and at the 

 Bergakademie at Freiberg. Returning to the United States he joined 

 the Fortieth Parallel Survey in 1867, a work admirably planned for 

 obtaining the greatest efficiency and speediest results in geological 

 reconnaissance. A large part of the geological results of this survey 

 is due to the painstaking and exact work of Emmons. 



When the U. S. Geological Survey was created in 1879 Emmons 

 was selected to take charge of investigations in economic geology. 

 The first important work completed was a monograph on the Lead- 

 ville district in Colorado, a region presenting most intricate problems 

 of mining geology. Emmons' monograph has been of the greatest 

 value and importance to the miners and it may be said that it is 

 the most monumental evidence of the value of geology to the min- 

 ing industry. In this and in the many later reports published by 

 Emmons the importance of "replacement" as a process in ore forma- 

 tion was strongly emphasized and it is one of his principal merits to 

 have made the mining engineer acquainted with this mode of nature's 

 operation, by which, for instance, ore bodies of galena take the place, 

 molecule for molecule, as it were, of strata of limestone. 



Space does not suffice to mention all the investigations and reports 

 which occupied his time. Among other mining districts he examined 

 may be mentioned Butte, Aspen, Mercur, Bingham, the Black Hills, 

 and Cananea. 



In 1900 he contributed a most important paper to the Institute of 



