PEALE.] 



GEOLOGY SECTION NO. 23. 245 



24. Coarse white conglomerate, 27 feet 3 inches. 



25. Greenish-gray micaceous sandstone shale, with hard sandstone bands; 



45 feet 11 inches. 



26. Yery hard blue limestone, irregular iu structure; brown on weathered 



surfaces. This limestone has the same character as the limestone 

 In the shaly sandstone iu section IS'o. 10; ]0 feet. 



27. Coarse gray sandstones with shales, 145 feet. 



28. Massive sandstones of a greenish tiuge. Mostly fine-grained and 



micaceous. Some beds are pebbly, and near the bottom there is 

 from G to 8 feet of black shale with carbonaceous material. The 

 upper part of the bluif on which these exposures are is conglom- 

 eritic, where the color is darker than below ; 205 feet 10 inches. 



29. Rather coarse gray sandstones iu these beds, weathering of a rusty 



color, fossiliferous ; 342 feet 4 inches. 



30. Space reaching to the summit of the h'll, and filled, in all probabil- 



ity, with sandstones ; 500 feet. 



All the beds in this section have a dip toward the northeast, the 

 angle of inclination varying from 10<^ to 25°. As we go down Eagle 

 Eiver, we find that the beds above gradually make their appearance, 

 and that the dip becomes more and more toward the north, until the 

 beds curve around the end of the range of which the mountain of the 

 Holy Cross is the last high point. Going eastward from the mouth of 

 Eoche Moutounes Creek the dip gradually decreases toward the Blue 

 Eiver range, where there is, as I already mentioned, no doubt a fault. 

 There is also, I think, a very small synclinal fold between Eagle Eiver 

 and the Blue Eiver range. 



In bed No. 29 of section No. 22 I found fossils which were submitted 

 to Professor Lesquereux, who has found the following species : Calamites 

 SucJiOvii, Brgt., Calamites gigas, Brgt., Stigmaria fucoides : of the first he 

 says : " This species is perhaps more abundant iu the coal-measures ; but 

 it ascends to the base of the Permian, where, iu Europe at least, it has 

 been found in plenty." The same species, however, was associated with 

 Calamites gigas, v^hi^h, Professor Lesquereux says, is exclusively Permian, 

 or has as yet never been found in the Carboniferous measures. Of 

 Stigmaria fucoides he says : " It is a universal species of the coal-measures, 

 also ascending, rarely however, to the Permian. I am inclined to con- 

 sider it as Permian merely by the lithological relations to the other 

 specimens, but it is not possible to decide positively from this." The 

 latter specimens were found somewhat lower (a few feet) than the other 

 specimens. The layer in which these specimens were found probably 

 lies near the line between the Carboniferous and Permian formations. 

 All below i^robably belongs to the Carboniferous. Two things are 

 especially noticeable here, namely, the small amount of limestone when 

 compared with the section made at Horseshoe, (section No. 18,) and 

 again the i^resence of so much carbonaceous material in the shales and 

 sandstones. We have seen in the section above that there are numer- 

 ous black shaly layers, but besides there are also in the sandstones at 

 various i^laces patches of black carbonaceous material. When these 

 layers were being deposited there must have been low, marshy ground 

 bordering this part of the Sawatch range. This range must therefore 

 have been i)artly above water, or at least not very far below the surface. 

 There may have been oscillations of the surface. 



The sandstones at the upper portion of the bluff, those in the latter 

 part of the section, are very much like those below the first fault on Four- 

 Mile Creek, (No. 24 of section No. 18.) I think they are of the same age. 

 Another season we may study these beds again, and above them I hope 



