Geology and Mineralogy. 467 



The most important ore bodies are those of the copper-bearing 

 sulphide deposits which occur in massive marbleized limestones 

 along particular beds in the vicinity of the intrusives. 



Mr. Boutwell sums up the geological history of the district as 

 follows : " Between Carboniferous and late Tertiary time monzo- 

 nitic intrusives invaded sediments in the Bingham area, meta- 

 morphosed them and introduced metallic elements which replaced 

 marbleized limestone with pyritous copper sulphides. After the 

 superficial portions of the intrusives had cooled to at least partial 

 rigidity they and the inclosing sediments were rent by northeast- 

 southwest fissures. 



" Heated aqueous solutions from the deeper unconsolidated 

 portions of the magma then ascended these channels, altered 

 their walls, and introduced additional metallic elements. At this 

 time more pyritous copper sulphide may have been added to that 

 formed earlier in the limestone in connection with contact meta- 

 morphism. Monzonite, including its original metallic constitu- 

 ents, w r as altered ; copper, gold and sulphur were probably added, 

 and auriferous copper sulphides were formed. The silver-lead 

 ore was deposited in the fissures, mainly by filling, partly by 

 replacement. 



"Since this period of mineralization these original sulphide 

 ores have been altered by surface waters, in their upper portions, 

 into carbonates and oxides, and relatively enriched in their under- 

 lying portions." w. e. f. 



1. Economic Geology, a Semi- Quarterly Journal devoted to 

 Geology as applied to Mining and Allied Industries. Volume I, 

 Number 1. (Published by the Economic Geology Publishing 

 Company, Lancaster, Pa.) — The appearance of the first number 

 of this new journal is an event of unusual interest and importance. 

 Economic geology has only within the last quarter century estab- 

 lished its place as a distinct and important department of geo- 

 logical science. In Germany the Zeitschrift fur prahtische Geo- 

 logie was the result of this movement among German geologists 

 and it has done much to place this branch of geology on a firm 

 basis both at home and abroad. It is only recently, however, 

 that in the English-speaking world economic geology has begun 

 to occupy its rightful position, and this new journal has been 

 established on account of this fact and with the hope that by its 

 efforts a still larger recognition may be given the subject. ITntil 

 now the American geologist who had interested himself in the 

 problems of ore deposits had no field for the publication of the 

 results of his investigations outside of the channels of the United 

 States Geological Survey, except in various technical or semi- 

 technical journals devoted to mining. It is, therefore, with a 

 distinct sense of congratulation that we find provided here a 

 proper place for the printing of such papers. 



The editor outlines the scope and office of the journal in his 

 first editorial as follows : " The chief purpose of ' Economic Geol- 



