2^2 The Irish Naturalist. [Nov., 1897. 



such as rushes, worms, &c. He also mentions that although 

 the springs are principally silicious, there are also calcareous or 

 ferriferous, and other springs, accumulating their special rocks 

 or minerals : he largely describes the travertines. Among 

 other facts recorded, is this interesting one, that the late 

 William Archer has in cold springs in Ireland found an alga 

 identical with one in the hot springs of Yellowstone. 



Although Weed's report has been published nearly ten 

 years, it seems to be generally unknown, even to those who 

 have visited the Yellowstone. This is to be regretted, as 

 some of the characters of quartz-rock would seem, to suggest 

 an organic origin. This communication, however, is not 

 controversial, but suggestive, and is written in the hopes that 

 it maj'' induce some of our numerous microscopists to ex- 

 amine the quartz-rocks for organisms. 



Considering that the quartz-rocks are of such great age, and 

 have been subjected to so many vicissitudes, it is not sur- 

 prising that algal remains or such like, may have gone unde- 

 tected, more especially when we remember that it is only quite 

 recently they have been authoritatively recognised in the 

 modern accumulation. In 1874, Dr, C C Parry noticed the 

 presence of Algae in the hot springs of Yellowstone, and said 

 they would reward special research ; but in 1878 Dr. A. C. 

 Peale scouts the idea of organic aid of the hot water accumula- 

 tion ; and it was not till after Prof Weed's researches were 

 published (1890) that we learned how animal and vegetable 

 life were such important agents in the accumulating of the 

 rock-masses — the adjuncts of the springs. 



The limit of heat at the Yellowstone in which Algae grow 

 is i85^F., but such plants are immature and poorly developed; 

 it is not till the temperature is lowered to 140° F. that they 

 attain their full development. Those grown in excessive 

 temperature are often so indistinct as to be nearly undistinguish- 

 able under the microscope, but in the rock they form riband- 

 like stripes, or concentric rings of colour. Such lines or 

 "dirt bands," as they have been called, are very characteristic 

 of quartz-rock, but as in the latter they are so mineralized, it 

 seems hard to expect to be able to prove skeletons of plants 

 in them, except possibl}- on the surface of the layers of 

 depositions, where there are serpentine lines and pinholes 



