110 EEPORT UNITED STATES GEOLOGICAL SURVEY. 



furious boiling pools, in which the water spurts but an inch or two, to those in which 

 it is thrown to a height of more than twice that number of feet. One bowl in par- 

 ticular, the largest in the group, is partly surrounded by a chimney nearly 5 feet 

 in height, and the water is occasionally thrown to a height of more than 6 feet, so as 

 to pass completely over this rim. The contents of this bowl are continually agitated, 

 and the constant but irregular thud of the successive impulses reminds one vividly of 

 the sound produced by the dashing of the water on a rock-bound coast. The chimney 

 is open on the side next the stream, thus allowing the overflow to pass off freely 

 in this dii'ection. * * * There are several smaller orifices, with correspondingly 

 diminished chimneys, but the majority of the minor springs of this group are mere 

 bubbling jets, in which the water is occasionally spurted to the height of a few iuches, 

 and these are not usually provided with raised walls. In all of these, however, there 

 is something of an approach to the same structure, and a few differ only in degree 

 from the largest bowl. 



Snlphureted hydrogen is evolved from some of these springs, and small deposits of 

 sulphur are found in favorable situations, but the chief and most characteristic ingre- 

 dient throughout is silica, of which the chimneys are mainly composed. 



Were we to classify these jets according to the character of the deposits alone, their 

 place would undoubtedly be among the geysers, for we find here not only a compo- 

 sition nearly identical with that of the products in the Fire Hole basins, but even the 

 peculiar structure of the geyser products is very closely imitated in the formations 

 about the bowls. About some of the smaller jets clear white deposits of the most 

 beautiful geyserite are formed, resembling porcelain beneath, with an upper surface 

 of delicate tracery, or of coarser excrescency, according to the force of the falling 

 water. Sometimes a glistening pink surface is disclosed by the fracture of the rougher 

 incrustations, which are usually of a light-brown color. Manganese in the form of 

 pyrolusite (manganic dioxide) is extremely abundant as a coating to parts washed by 

 the outflow and by the falling spray, as well as on portions of the interior walls of 

 many of the bowls. Iron is not scarce, being more particularly present exteriorly, 

 where it gives rise to the brown and pink colors which are visible in the siliceous 

 crust, and it is noticeable that the growth of green cryptogamic vegetation in the 

 water is especially abundant in those spots where iron is most common as a deposit. 



This group of springs was first described by Captain Barlow, who met 

 with them on his trip from the Yellowstone Eiver to the Geyser Basins. 

 He says:* 



Ten miles west of the river we came upon a very hot stream, formed from the over- 

 flow of a large system of springs, in some respects more interesting than any we had 

 yet encountered. One, with a curious crater, was constantly throwing up boiling 

 water to the height of several feet. The crater is of calcareous [siliceous?] rock, 6 

 feet in diameter, and bears a strong resemblance to a human ear. A beautiful branch 

 joins this stream from the northwest, cool and highly impregnated with ahim. The 

 water from these springs is remarkably clear and colorless, except that from a single 

 one, which had the bright color of gamboge. On both sides of the hot stream the 

 ground is a soft, hot marsh, very dangerous to examine, and it is only in the immediate 

 vicinity of the largest springs, where a rocky deposit has been formed, that one is 

 entirely safe. A steam jet, flowing beneath tlie surface of the water into the stream, 

 at one point presented a very interesting appearance, and gave oft' a very novel sound, 

 something like that made by the spindle of a spinning-machine. 



The spring with the crater is the one described by Professor Comstock. 

 Captain Barlow is the discoverer of the group. We passed to the west- 

 ward of them in 1871 and south of them in 1878, so that I have never 

 seen the group, which is especially interesting from the occurrence of 

 manganese in its deposits. 



Dr. C. L. Heizmann, in his report on the mineral and thermal waters, 

 speaks as follows of the springs on Alum Creek : + 



All along its banks were hundreds of boiling and bubbling springs and remains of 

 extinct ones, all of which may be classed with the last [i. e. mad volcanoes and tnrhid 

 lake springs], although there is a greater profusion of clear alnm springs, evolving 

 only snlphureted hydrogen, intermixed with the others, than elsewhere. One, near 

 the head of the stream, was for the most part walled (6 feet high) by its deposit on 

 small timber, which, partially silicified, gave it the shape of a yellowish-brown, 

 snaggy cone. Although not exactly like a geyser, it nevertheless threw constantly 



*Recounaissnnce of the Yellowstone Eiver, Senate Ex. Doc. No. 66, 42d Congress, 

 2d session, p. 19. 



t Report of Reconnaissance of Northwestern Wyoming, 1873, 1875, by Capt. W. A. 

 Jones, p. 302. 



