PROCEKDINGS OF THE COTTESWOLD CLUB 27 1 



own separate sul)tenanean source, its own times and 

 peculiarities of eruption. 



I proceeded four or live miles up the river before 1 

 came to anv more j)rominent signs of volcanic activity. 

 Then, emerging from a luxuriant pine-grove, I saw before 

 me what I should be fully justified in calling the " Black 

 Country" of the Rockies, if it were not for the fact that 

 everything in it except the pines was brilliantly white, 

 especially as seen through the clear mountain air and 

 under the rays of an August sun ; white plateaux of 

 geysirite, white crater-mounds, white foaming river, white 

 clouds of steam, white, or rather, crystal-clear columns of 

 water. This was the Upper Geysir Basin of the Firehole 

 River, a tract about three miles long and two miles broad, 

 containing more geysirs and hot springs than any other area 

 of the same size in the world. At least 50 of these are 

 of the first rank, but I shall, of course, only attempt to 

 describe a few, possessing characters of special scientific 

 interest. 



The flat bottom of the valley is wholly composed of a 

 stratum of geysirite of unknown thickness, probably at 

 least 40 or 50 feet, produced by the decomposition of the 

 underlying lava sheet under the influence of heat and 

 moisture. The silica, passing into solution, as has been 

 already explained, has been brought to the surface by the 

 geysirs and hot springs and then deposited from the water 

 in sufficient quantity to form these thick and extensive 

 layers. [Lantern slides.] 



I noticed on the ground in several places large slabs of 

 what looked so exactly like the semi-transparent, elastic, 

 gelatinous flesh of fish (if I may say so) that I had to 

 tear off a bit and taste it in order to satisfy myself that it 

 was really nothing but colloidal silicon hydrate recently 

 deposited from the water as it cooled. [Specimen shown.] 

 Some of it, left for a while in the hot sun, soon gave off 

 the elements of water and crumbled down into a friable 



