82 EEPOET UNITED STATES GEOLOGICAL SURVEY. 



from the bluff like a spur. Near the beginning of the mound are sev- 

 eral small holes, from which there is a slight escape of water that trickles 

 down the side of the mound. The temperatures are 143° F., 144° P., and 

 144° F. At the head the mound is about 25 feet high. It extends to- 

 wards the oblong mound (Glen Grotto) and diminishes gradually in height 

 until it ceases, and the line is continued by several broken mounds and 

 cones. 



No. 40 marks the site of several springs farther down the mound; the 

 temperature is 105° F. At this point, on the west side of the mound, 

 there is a marshy area with several pools of water. 



No. 41 is a spring on a low mound, with a temperature of 128° F. Here 

 the ridge runs out into the marsh, and beyond are several old cones, 

 remnants of the ridge. West of these cones and dead mounds are 

 marshy spots with oozing springs. Below them are the following 

 springs: 



No. 42. — This is a spring 4 feet in diameter, from which bubbles of 

 carbonic acid gas escape. The temperature is 105° F. Above it are 

 several holes from which water oozes, near the road. Here the tempera- 

 tures are 102° F. and 112° F. 



No. 43. — Two oozing holes between No. 42 and the road; the temiDera- 

 tures are 103° F. and 110° F. 



No 44 is nearest to the road, and has a temperature of 125° F. 



These springs just described are all somewhat concealed in the grass, 

 and all give off carbonic acid gas. 



No. 45 is a low, flat, oblong mound, in which the present openings mark 

 what was probably once a fissure extending along its entire length. At 

 present the fissure is closed, and in the small cones we have shown, on 

 a small scale, the process by which the larger mound was built, viz, by 

 the overflowing water depositing layer upon layer. There are three 

 cones and one flat-rimmed spring. The temperatures range from 107° 

 F. to 135° F. 



No. 46. — At the north end of the Glen Grotto, between it and the mound 

 of No. 46, are two small cones, one of which has an active spring and 

 the other dead. There is also a small spring. The temperatures axe 

 130O F. and 136° F. 



The slope of the mound above these springs is constantly wet by the 

 water that flows from the springs on the summit. 



No. 47. — Glen Grotto (Plate Yl,a.) This oblong mound is about 50 feet 

 in length by 25 or 30 feet wide, and is about 20 feet above the general 

 surrounding level. The wagon-road passes near one end of it, so that it 

 is readily found. On the summit there are seven or eight cones, five of 

 which have active springs. Besides these there are a number of old 

 holes that once were occupied by springs, a. Throws the water out 

 with a spurt which reaches 5 or 6 inches in height. It has a tempera- 

 ture of 148° F., and is surrounded with a coating of sulphur, b. Also 

 bulges, and has a temperature of 148° F. c. d. and e. Have tempera- 

 tures, respectively, of 130° F., 106° F., and 147° F., and are bubbling 

 springs. 



The cones which these springs have formed are from 6 to 8 inches in 

 height, and show the same method of formation that the large mound 

 does, viz, the overlapping layers. The sides of the mound are colored of 

 a rusty yellow in places, and dead trees stick through the deposit, having 

 been killed by the hot water and the accumulation of the Calcareous 

 sediments. The springs present about the same appearances noted in 

 1871 and 1872. In the former year the temperatures ranged from 142° 



