220 GEOLOGICAL SUEVEY OF THE TEKRITOEIES. 



are about 500 feet higli, rounded in outline, and extending about three 

 miles in widtb. On the east we descend into another valley, G, in which 

 all the rocks are concealed by the drift. I have little doubt, however, 

 that it is underlaid by Tertiary sandstones. This valley is somewhat 

 irregular in shape; but in the section it is represented at C as about six 

 miles in width. From qto r the line on which the section is made is 

 changed, and has a course of south 45° east. The Tertiary sandstones, 

 which we have just spoken of, are the same that we noticed extending 

 to the edge of the trachytic hills in the northern and northwestern part 

 of the park. We have seen that they extend across the park in a wave- 

 like manner, occasioned, no doubt, by volcanic action that was contem- 

 poraneous with the elevation of the volcanic ridge on the east side of 

 Trout Creek. Eeturniug to this ridge, and following it southward, we 

 observe that it turns more and more to the eastward; and this fact is 

 also rendered evident when we notice the course of the streams that are 

 parallel to it. At Station No. 92, a high point to the southeast, which 

 seems to mark the termination of the ridge, we have, on the south side 

 and dipping toward the south, as I learn from the not^s of Mr. Taggart, 

 an outcrop of sandstone, somewhat metamorphosed. This I take to be 

 the bed of sandstone so characteristically marked as Cretaceous No. 1. 

 It evidently belongs to the western side of the synclinal fold, to which I 

 have already referred as existing at the head of Trout Creek. Still far- 

 ther down the river, and on the eastern or rather northeastern side, is 

 another butte, in which I found exposures of beds belonging to the Da- 

 kota group. The sandstone here, being very* much metamorphosed, is 

 quartzitic. Just above it are the same shales that we saw in other places, 

 and the limestone, with Cretaceous fossils, (bed No. 2, in section No. 

 1, and No. 67, in section No. 9.) These beds all dip to the southwest at 

 an angle of 50° to 60°, and are, I take it, a prolongation of the eastern 

 side of the fold on Trout Greek, and at the butte (Station No. 92) referred 

 to by Mr. Taggart. The volcanic ridge, which is the cause of the uplift 

 on the eastern side, making a turn to the eastward, of course, the strike 

 of the sedimentary beds is also to be found turning in that direction. At 

 the base of the butte just referred to are remnants of a soft sandstone, 

 which I consider to be of Tertiary age, whether Eocene or more modern 

 I could not determine. Before leaving this butte I will describe the 

 springs that are at the south end. They are all saline. There are four 

 principal springs, although there are beside a number of places where 

 the water bubbles up. Spring No. 1 is about two feet in diameter and 

 three feet in depth, and has no doubt been artificially enlarged. At 

 intervals of a few seconds there is a slight escape of gas, probably all 

 carbonic acid. The water has rather a pleasant taste, though by no 

 means as agreeable as that in the springs at Manitou. It is saline, 

 somewhat pungent, tasting slightly also of sulphur. The temperature 

 of the water was 58° Fahrenheit ; the air being 78° Fahrenheit. 



Spring No. 2 is about 6 feet below No. 1, and about a foot in diameter 

 and 6 Inches deep. The water tastes very much like that of No. 1, 

 although not quite so pungent, nor is there as large an escape of gas. 

 The temperature was the same as that of No. 1. 



Spring No. 3 is very little different from the other two. It is about 4 

 feet from No. 2, and has a greater evolution of gas. The temperature 

 is still 58°. 



Spring No. 4 is about 30 feet from No. 3, and about a foot in diameter 

 and 6 inches deep. It is a very quiet spring, the water tasting strongly 

 of salt, and also slightly of sulphur. Between No. 3 and No. 4 is a 

 marshy space, in which, by a little digging, a spring could be formed. 



