FFALE] HAYDEN's valley SPEINGS BRIMSTONE GEOUP. Ill 



its water (194°) with great violence against its sides and 8 feet into the air. It con- 

 tained liane, iron, alumina, magnesia, sulphides, sulphates, and chlorides, and evolved 

 sulphureted hydrogen but no carbonic acid. All of the springs surrounding it, very 

 numerous and close together, evolved carbonic-acid gas, but, strangely, some of them 

 only it and sulphureted hydrogen. 



The creek above, besides being supplied by many small sx^riugs (100°-180°) on its 

 banks, contains in its bed many bubbling carbonic acid gas, but no sulphureted hy- 

 drogen. 



The temperature of the running water here was 84°. However, a tread or the mere 

 piercing with a stick of its sandy bottom anywhere witbiu one-half mile started a 

 thin, hat, and unbearable stream, containing carbonic acid gas, but no sulphureted 

 hydrogen. Of course, as its flow was only momentary, its relative temperature could 

 not be got, but the temperature of the surface sand, where no visible spring existed, 

 was the same as that of the water, 84°. Above the point where the camp was made, 

 and where this phenomenon gradually disappeared, the water of the creek was j)ure 

 and potable. 



HOT SULPHUJi SPRINGS, OR BRIMSTONE GROUP. 



This is a collection of fumaroles and solfataras at the head of Alnm 

 (Warm Spring) Creek, near the divide between the East Fork of Fire 

 Hole River and the Yellowstone drainage. On the map of the Park it 

 is indicated as Hot Sulphur Springs, and Professor Comstock, in his re- 

 port, names it " Brimstone Group." It is south of the Boiling Springs 

 Group, and was passed by our party in 1871, and is mentioned in my 

 report for that year.* Captain Barlow also passed them after leaving 

 the Boiling Hot Springs already described. The Howard wagon road 

 passes the springs, or rather fumaroles, for the latter predominate. Dr. 

 Hayden thus describes this locality : t 



There was one locality, where the deposit covered several acres, that presented a 

 most attractive picture. The entire area was thickly covered with conical mounds 

 of various sizes, ranging in diameter from a few inches to a hundred feet or more, and 

 these cones, or hillocks were full of orifices, from which steam was issuing. All these 

 little chimneys, or orifices, were lined with the most brilliant crystals of sulphur, and 

 when the heated crust was removed we found the under side adorned in the same 

 manner. The basis of the deposit was silica, as white as snow, but it was variegated 

 with every shade of yellow from sulphur, and with scarlet or rose color from oxfde of 

 iron. Ill the distant view the appearance of the whole country may be not inaptly 

 compared to a vast limekiln in full operation. 



Captain Barlow, describing this area, says:| 



Then we came upon an immense area covered with sulphur vents, each hillside con- 

 taining thousands of these little crystal chambers, which, upon being broken into, 

 sent forth quantities of sulphuric steam. In passing through the orifice from below, 

 this vapor had been sublimated into beautiful crystals of pure sulphur, varying in 

 dimensions from the size of a needle to the thickness of the finger, while some were 

 even larger. The country presents the appearance of a vast limekiln in active com- 

 bustion. The crust of soft white rock was exceedingly thin, requiring great caution 

 in picking a route for the animals. 



Professor Comstock, speaking of these springs, says.§ 



The time spent in this locality was not sufficient to allow of much careful work, and 

 the nature of all the products was, consequently, not ascertained. Sulphur, however, 

 is the principal ingredient, being probably produced here in greater quantity than in 

 any other portion of the National Park thus far described by the several authorities. 

 There are some bowls of considerable size, but the most striking feature of the whole 

 area is the occurrence of a large number of small orifices, m which the water bubbles 

 constantly, giving rise to deposits of crystallized sulphur, which are formed upon the 

 walls of numerous cavernous incrustations. 



There are really two groups of springs, from one of which quite a 

 large stream of water passes. There are a number of sulphurous ponds 



* Eeport United States GcAgical Survey for 1871, 1872, p. 182. 

 t/Wrf, p. 102. 



tEeconnaissance of the Yellowstone Eiver, Senate Ex. Doc. No. 66, Fortj'-socond 

 Congress, second session, p. 19. 

 ij Eeport of Eecounaissauce of Northwestern Wyoming, p. 221. 



