I897-] 5^1 



THE POSSIBI^E ORGANIC ORIGIN OF QUARTZ-ROCK. 



BY G. H. KINAHAN, M.R.I. A. 



In the Proceedings R. I. A., 3rd ser., vol. iii., no. 4, is pub- 

 lished a paper on Quartz, Quartz-rock, and Quartzite. In it is 

 reiterated my previous conviction that the protrudes of quartz- 

 rock had an analogous genesis to that of the silicious adjuncts 

 of the modern hot springs. Not being occularly acquainted 

 with such springs, but only with their products, information 

 in connection therewith was asked for in America, and kindly 

 offered by Walter Harvey Weed, U.S. Geol. Survey, who sent 

 a copy of the Bulletin containing his report on the ** Forma- 

 tion of the Travertine and Silicious sinter by the Vegetation 

 of Hot Springs" {Extract, gtk A7inual Report of the Director, 

 1887-88), with specimens. They, however, through some vagary 

 of the American postal arrangements, did not arrive till six 

 months after date, and consequently not till after the above- 

 mentioned paper had been published. This, to me, was un- 

 fortunate, as Prof Weed's researches exemplify the probable 

 correctness of my suggestion. 



In his report on the accumulation of the hot springs of 

 Yellowstone National Park, Weed mainly confines himself 

 to the effect due to organisms ; but in his letters he states — 

 *' The Yellowstone deposits are extremely variable in charac- 

 ter, accordingly as they are produced by the action of 

 organic life (Algae), or by evaporation from true geyserites, or 

 by the precipitation of the silica due to cooling and relief of 

 pressure, or due to the cementation of comminuted fragments 

 of sinter formed by other agencies." 



The specimens sent were solely to illustrate the action 

 of organic life, but he further writes : — 



" I have, of course, a great variety of sinters from the Yel- 

 lowstone, embracing everything from those formed by eva- 

 poration purely, those formed by the solidification of particles 

 which have separated from the highly charged waters and 

 formed a deposit, to those which are in part argillaceous, and 

 which are so largely formed in this manner." 



Although in the Yellowstone the secreting organism is 

 principally an alga, in the report he mentions other agents, 



