PROCEEDINGS OF THE CANADIAN INSTITUTE. 



39 



The Occurrence of Gold in Some Rocks in Western Ontario. By 

 J. W. Bain, Esq. 



(Read April 22nd, 1899). 



Of mauy speculatious on the origin of metallifeiou.s lodes, perhaps none has 

 attracted more attentiou than that which is known as the theory of lateral 

 secretion, and the object of this note is to discuss in brief its pos.sible application to 

 some ore deposits of Western Ontario. 



Delias in 1770 and Gerhardt in 1781 concluded that rain penetrated the earth, 

 taking up any soluble material in its path, and, afterwards collecting in the fissures 

 and cavities, gradually deposited the dissolved matter with the formation of a 

 metalliferous lode. This is a fair description in general terms of the theory of 

 lateral secretion, and for the next ninety years the idea lay fallow. In 1873, 

 Saudberger in Germany commenced a series of investigations for the |)urpose of 

 determining whether the theory were tenable, and the ores, veinstones, and country 

 rocks of a number of veins, were subjected to careful analysis, particular pains 

 being taken to detect and estimate small quantities of certain elements. The 

 hornblende, augite, olivine and mica of the rocks were isolated, and in them could 

 be detected appreciable cpiantities of almost all the elements commonly occurring 

 in metalliferous veins. Sjiace will not permit of any lengthened description of 

 these interesting researches, which resulted in the author's adoption of the theory, 

 but attentiou may be directed for a moment to the United States, where steps were 

 being taken to collect evidence upon the subject. Geo. F. Becker was commissioned 

 by the Geological Survey to examine the Comstock Lode, and during the work an 

 investigation similar to Sandberger's, though on a much smaller scale, was carried 

 on. The results which were published in 1882 led the geolgist to the belief that 

 lateral secretion would satisfactorily account for the origin of the lode. 



J. S. Curtis, reporting on the Silver Lead deposits of Evireka, Xevada, con- 

 cluded that the theory was capable of explaining the origin of these ore bodies also, 

 and S. F. Emmons, in a monograph on the Geology and Mining Industry of Lead- 

 ville. Col., describes some experiments which led to a similar view. 



These opinions "were witnessed by an array of analytical results, which dealt 

 almost entirely with gold and silver, gold being determined only qualitatively. In 

 view of these facts, it was decided to make some investigations upon Ontario ores. 

 The methods were rendered as accurate as possible, and, although they differ 

 somewhat from others which have been used, the changes were confined to details, 

 with, it is believed, beneficial results. 



The samples examined were country rocks, taken from 6 to 10 feet distant 

 from the vein ; the following are the results : 



Foley mine — gold 6c. to 17c. per ton. 



Mikado " " 12c. to 28c. 



Regina " " 3c. 



Sultana " '• none. 



Granite, protogene, at least 500 feet from 



any vein — gold none. 



In endeavouring to estimate the value of these results, it must be remembered 

 that more than one interpretation may be placed upon them. If we assume that 

 the mineral-bearing solution can permeate the rock with a certain degree of freedom, 

 and this premise is one which we can make with confidence, solutions from under- 

 ground sources capable of depositing minerals would imitreguate tlie couutry rock 

 for some distance and produce a condition, close to the vein, resembling that 

 which would result from lateral secretion. For this reason, a series of samples 

 taken at points increasingly remote from the deposit, would yield results of nuu^h 

 value, if it m ere possible to estimate with great precision the amount of gold 



