86 SURVEY OF COLORADO AND NEW MEXICO. 



the water flows. They are properly ^' Hot Sulphur Springs," varying in 

 temperature from eighty to one hundred and twelve degrees. 



About fifteen miles west of the springs is the valley of the Troublesome 

 Creek, a small brancli of the Grand Eiver, flowing from the basaltic 

 mountains on the northern side of the i)ark. 



I visited this region under the guidance of Mr. Sumner, an old resident 

 of the park. The surface of the country along our road was strewn with 

 eruptive rocks. We saw several localities where the basaltic rocks 

 protruded, and one place in Corral Creek, about eight miles west of 

 Grand Eiver, where the little stream has cut a deep channel through 

 the red granites. The older tertiary beds appear from time to time. 



Troublesome Canon, at the head of the creek bearing this name, is 

 entirely basaltic, and the rugged walls not only of the main stream. iDut 

 also of the little branches, form a most picturesque view. 



Below the caiion, the valley of Troublesome Creek, and also that of 

 Grand Eiver near the junction, is occupied by belts of modern tertiary 

 sands and marls like those observed at the entrance to the park, by 

 Berthoud's Pass. Where the little stream cuts the terraces, horizontal 

 strata of whitish and flesh-colored sands and marls are exposed. I looked 

 in vain for fossils and found only specimens of silicifled wood. There 

 are cold sulphur springs in this valley. All through the park, the 

 benches or terraces are conspicuous in the vicinity of streams, as at the 

 base of mountain ranges. In the park through which Frazer's Creek 

 flows, these benches or terraces are most beautifully carved out from the 

 modern marls. 



1 regret that my visit to the Middle Park was so short that I could 

 not explore the entire area with care, for few districts in the West can 

 aflbrd more material of geological interest, and an entire season could 

 be spent studying its geology and geography with great profit. 



The agricultural resources of the Middle Park are as yet unknown. No 

 attemi^t has been made to cultivate any portion of it. Grass and graz- 

 ing are excellent and the soil good, and if the climate will permit, all 

 kinds of garden vegetables could be raised in abundance, and some 

 varieties of the cereals. Timber is abundant both for lumber and fuel. 



In summing up the geology of the Middle Park, we find that aU the 

 sedimentary rocks known in this country are found there. I did not see 

 any beds that I could define as carboniferous, but the triassic, Jurassic, 

 cretaceous, and tertiary are well developed. I have no doubt as to the 

 existence of true carboniferous limestones in the Middle Park. 



The tertiary deposits of this region may be divided into two groups, 

 viz, the lignite or older tertiary, and the modern i)lioceue marls and 

 sands which seem common to the parks and mountain valleys. The for- 

 mer conform perfectly to the older beds, while the latter seldom incline 

 more than three to five degrees, and do not conform to the older rocks. 

 The marl groui)is undoubtedly contemporaneous with the Arkansas and 

 Sante Fe marls. 



The geologica Istructure of the Middle Park is more varied, compli- 

 cated, and instructive than that of any other of the parks. 



