BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



Vol. 15, pp. 1-28 January 27, 1904 



THEORIES OF ORE DEPOSITION HISTORICALLY CONSIDERED 



ANNUAL ADDRESS BY THE PRESIDENT, S. F. EMMONS 



(Read before the Society December 30, 1903~) 

 CONTENTS 



Page 



Introduction 1 



Prehistorical views 2 



Development of knowledge historically considered 3 



The three periods , 3 



The speculative period , 3 



The scientific period 9 



The verification period 19 



Results achieved 28 



Bibliography 28 



Introduction 



In the city in which we meet this year an exposition is preparing which 

 is designed to commemorate the peaceful acquirement a century ago of 

 the rights of France to the Mississippi valley and the regions to the west. 

 It was the metallic wealth of the valley region which first led to its ex- 

 ploration by the French, and which still constitutes an important feature 

 in its industry, yielding annually, as it does, an amount about equal to 

 the original purchase price. To a still greater degree has the unexampled 

 rapidity with which, in the last half century, civilization and industry 

 have spread over the mountainous regions of the West been due to the 

 development of their mineral resources — a development to which geolog- 

 ical science has in no small measure contributed. 



In selecting a subject for my address as President of the Geological 

 Society of America, it has seemed appropriate, therefore, both to the 

 time and to the place, to choose a theme that has to do with that branch 

 of geology which is especially concerned with the deposits of the metals. 

 The history of theories of ore deposition was the subject originally chosen, 

 but, as it gradually developed in the course of research, it was found that 



I— Bull. Geol. Soc. Am. Vol. 15, 1903 (1) 



