PEALE.] HAYDEN's valley SPEINGS — MUD VOLCANOES. 101 



All the time we were at the locality we saw no eruption of mud, and 

 still the coating of the trees appeared to go on. This led to investiga- 

 tion, which appeared to x)rove that the mud is carried up mechanically 

 instead of being erupted. The following on the subject is taken from 

 my report for 1872 : 



Last year, when at this locality, we noticed that the trees near the Giant's Caldron 

 had their branches coated with mud, and the question was raised as to how the mud 

 got there; we concluded that the geyser sometimes ejected its contents. This year, 

 however, investigation seemed to prove that the mud is carried up mechanically, 

 mixed with the steam that is constantly rising from the caldron, and that the spring 

 never has any eruptions. We were led to this opinion first by noticing that it was 

 only the under side of the branches that held the mud. Mr. Holmes then placed some 

 dead branches in such a position that the steam came upon them, and in a few hours 

 they had a coating of mud. Again, some of the trees on which the branches are coated 

 are living, which would hardly be the case had they received the mud from an erup- 

 tion. Another reason also is found in the fact that the surface of the spring is con- 

 stantly agitated, which is rarely or never the case with a true geyser. Still, in the 

 past it may have been a geyser and had regular eruptions.* 



1873. — Professor Comstock of course did not see the caldron, as he was 

 on the opposite side of the river, but he evidently noticed the column of 

 steam from it. He says : 



Dense clouds of vapor may be seen issuing from these localities at certain hours, 

 and the thiimping mtise produced by the throbbings of the agitated mud of the 

 salses may be distinguished without difficulty at a considerable distance.! 



1874. — The Earl of Dunraven refers as follows to the Giant's Caldron : 



This caldron is filled with thin mud in a state of most fearfully wild commotion, 



} boiling, spitting, and spluttering like a pot full of stirabout screeching hot. The 



' roar of it can be heard at a considerable distance, and the steam of it ascends in a 



dense column to heaven. A slight smell only of sulphureted hydrogen is noticeable 



here, but with many of these mud springs not only does the steam ascend to heaven 



but the stench also.j 



The condition of the spring in 1874, therefore, appears to be about as 

 it was in 1871 and 1872. The steam still escaped with a roar. Ludlow, 

 in 1875, makes no mention of the caldron. 



1878. — We noticed little if any change. Perhaps the noise made by 



the escape of the steam is not so great, but the column is still dense 



I enough to prevent our getting the temperature of the muddy contents. 



From the descriptions quoted it is evident that there has been a de- 

 crease in the power of this mud spring, for it is a constantly agitated 

 spring and not a geyser, since it was seen in 1870. When seen by the 

 Washburn party it was probably new. The fact that trees still alive 

 were crushed under the rim of the crater would seem to prove this, as 

 do also the force and violence described by both Doane and Langford.§ 

 A portion of the mud surrounding it was probably ejected, as they sup- 

 posed, by eruption, but it occurred, I think, when the volcano first broke 

 out. The mud on the trees, as I have indicated, is probably deposited 

 from the steam; at least we know that it will thus form, and as Doane 

 says in his report,]! the elevation to which it would have to be carried 

 would have to be very great to account for the lateral distribution of 

 the mud, as the vent is small. The lateral distribution is easily accounted 

 for, if the steam carries it, and the wind blowing from different directions 

 at different times would be sufficient to coat the trees on all sides of the 

 crater. Even when Doane, Washburn, and Langford saw it in 1870, 



•Report of II. S. Geol. Surv. of Terr, for 1872, p. 113^ 



tEeconuaissance of Northwest Wyoming in 1873, by Capt. W. A. Jones, p. 196. 



tThe Great Divide, p. 248. 



$ Langford describes the Mud Volcano in Vol. II of Scribner's Magazine, p. 17. 



II Yellowstone Expedition of 1870, p. 18. 



