PEALE.] MAMMOTH HOT SPRI^^GS OF GAEDINER's RIVER. 81 



In the timber growing on these terraces we have the evidence of the 

 great age of the springs. It is impossible, of course, to even estimate 

 the number of years. We do not know the thickness of the sediment, 

 and after the springs which deposited it ceased their action it may have 

 been a long time before the conditions were favorable for the growth of 

 the pines which we now see growing there, and yet some of them have 

 a diameter of nearly three feet, which would be equivalent to a growth 

 of more than five hundred years. In some places, after the trees gained 

 a foothold, new springs broke out, and killed them. It is probably true, 

 as Dr. Hayden said in 1871, " that all the deposits in the immediate 

 vicinity of the active springs are constantly changing from the margin 

 of the river to the top of the White Mountain and return." The de- 

 posits in these upper terraces are of great extent, but the water flowing 

 from them now is comparatively small in quantity, and the temperatures 

 with but one exception are low. 



No. 29.— This spring is on the edge of the thirteenth terrace, just 

 above the point from which starts the ridge that separates the eleventh 

 from the twelfth terrace. It is at a considerably higher level, and between 

 the springs and the beginning of the ridge is a succession of basins 

 built by the water which comes from above. The water spreads and 

 runs into a sink-hole. The basin of the spring cannot be defined 5 thern 

 are three holes from which the water, which has a temperature of 164° 

 F., escapes. 



]S"o. 30 is a small mound in a somewhat isolated basin, which will be 

 found best by reference to the map. It has two openings from which 

 water flows. The temperatures are 120° F. and 121o F. 



^o. 31. — This is the northern end of the ridge or mound on which 

 ISTos. 34-38 are situated. There are three small conical chimneys, each 

 about an inch in height, from which there is a slight flow of water, with 

 temperatures of 112° F., 120° F., and 125° F. This portion of the mound 

 is covered with a growth of pines, which obscures the situation of the 

 springs. 



No. 32. — This is a pool 150 feet in length at the foot of a gully, with 

 a mound of deposit on both sides. The water is generally clear and has 

 several points of ebullition. The temperature is 91° F. Back of this 

 spring there are mounds and ridges, after crossing which we come out 

 into the open space in which Glen Grotto and other mounds are situ- 

 ated. They will be described farther on. 



No. 33 is a round spring, about 20 feet in diameter, with a tempera- 

 ture of 890 F. 



Nos. 34-38 are small cones on the top of a long ridge-like mound of 

 deposit that is 10 feet in height and has a length of about 200 feet. A 

 number of the cones are extinct as regards the springs. The tempera- 

 tures given in the table range from 141° F. to 156° F. Following the 

 mound southward we find an old fissure, overgrown with cedars, and a 

 short distance beyond this the fissure contains a little warm water. Still 

 farther north are the springs described under No. 32. This ridge forms the 

 eastern boundary of a level which reaches westward to the wagon-road. 

 Back of this, which is the fourteenth terrace of the description in my 

 report for 1872, is a high blulf of deposit, covered with a thick growth 

 of pines. This immense mass of deposit extends to the head of the 

 gully. It is covered generally with soil, which obscures the old basins. 

 Traces of the ruins can still be seen at places. At the foot of the bluff 

 which marks the northern end of this mass are several cones or mounds 

 and a ridge similar to the one just described. 



No. 39 marks the i)osition of the ridge just mentioned. It extends 

 6 H, PT II 



