EKDUCH.! CRETACEOUS NO. 2. 225 



at an elevation of 8,934 feet, while camp 58, on the Florida, immediate- 

 ly below the station, is 7,530 feet. The shales of No. 2 have attained a 

 very considerable development here, and are covered by the yellow 

 sandstone, containing fragments of Inocerannis. For nearly a mile 

 along the northwest face of the very steep bluff, a series of " troughs" are 

 worn out in the shales, extending downward toward the stream. ISTar- 

 row strips of the shales, from 80 to 150 feet high, separate the single 

 " troughs." Where the steepest portion of the bluff ceases, these nar- 

 row strips show a bulging up of their ridges. Among themselves the 

 troughs are parallel and devoid of trees, except in the vicinity of the 

 stream. Probably they have been produced by snow-slides. An accu- 

 mulation of any considerable amount of snow in a region where the sun 

 has great power, even early in the season, could produce slides from 

 these steep bluffs that would readily accomplish the destruction of veg- 

 etation and give rise to the formation of these trough-like depressions. 

 In a horizontal direction the dip of the upper sandstone on these bluffs 

 varies. Instead of being almost due south, as that of the underlying 

 strata, it shifts to east of south on the east of the Animas, and toward 

 the west on the other side. The older sedimentary formations extend 

 southward in the shape of a wedge, and the younger ones dip oft' from 

 them, changing their strike, as the form of this wedge may require. 

 EidgeKo. 2 runs about 22° south of west from station 47 toward the 

 Animas, and is then continued on the other side.' Station 41 is located 

 upon a prominent point of it, 2^ miles west of the river. A section 

 taken through station 47 (Section VI), running northwest to southeast, 

 will show the vertical distribution of strata. Below the Cretaceous beds 

 we find the red Carboniferous sandstone, a, extending eastward from 

 station 40. Its dip is about 10°, a little east of south. 



Above it appears Cretaceous No. 1, &, beginning with white sandstones, 

 of less thickness than further west; but the succeeding strata, c, com- 

 prising yellow sandstones and shales, show a better development. In our 

 section this forms the bed of the Florida. Traveling beyond the stream, 

 towards station 47, a low bluff is passed, the highest point of which is 

 formed by a yellowish sandstone, d, which closes No. 1. Here the dip 

 has already increased to about 18°. Above this the gray shales, e, of 

 No. 2 commence; first forming a gently-rising slope, then a steep bluff, 

 which is caj)ped by two strata of yellow sandstone,/, c; the lower one 

 is shaly, scaling off in thin plates, and contains numerous remains of 

 j)lants, in a very poor state of preservation, while the upper is a com- 

 pact, fine-grained sandstone, weathering in rounded forms. It is the 

 one that forms the highest portions of ridge No. 2, and upon it station 

 47 is located. A depression occurs beyond this, occasioned by sandy 

 shales, h. Between this last stratum and the one preceding, coal is 

 found in some localities, but here none was observed. Overlying is a 

 bed of yellow sandstone, i. Probably this might correctly be regarded 

 as the terminus of No. 2, but discrimination between the two groups 

 becomes so difficult in this region that no positive assertion as to the 

 precise location of the boundary can be made. Then follow two beds of 

 yellowish to greenish shales, /<;, I, the lower one darker than the upper. 

 A thick bed of yellow sandstone, m, forms ridge No. 3, upon which sta- 

 tions 44 and 45 were located, the former 3 miles east of the Animas, the 

 latter about 6 miles west. At the point where our section cuts this 

 ridge, it is already of less prominence than further west. Higher up 

 in the succession of strata a series of light-colored shales, n, containing 

 strata of limestones, o, occur, covered again by the same shales, jj. 

 These belong to Cretaceous No. 3, and form very characteristic " hog- 

 15 H 



