ekdlich.] CARBONIFEROUS. 215 



absence of fossils was particularly noticeable iu the upper division, in 

 the red sandstones. With their aid, i. e., with the aid of typical forms, 

 any lingering doubt regarding their age could have been cleared satis- 

 factorily. As it is, only a few organic remains were found, and it be- 

 comes necessary to employ stratigraphical evidence in support of any 

 view that may be entertained with regard to their age. 



While the lower division of the Carboniferous is composed of a 

 series of beds, containing sandstones, shales, and limestones, the up- 

 per is confined almost entirely to the massive beds of red sand- 

 stone. Iu its lower strata the former shows mainly yellowish sand- 

 stones, interstratitied with yellowish and gray shales, while, higher 

 up, the blue limestones set in, containing characteristic fossils. Imme- 

 diately above that the red sandstones begin, and contiuue in an un- 

 broken series until the white sandstones of the Lower Cretaceous are 

 reached. Trias and Jura are missing or reduced to a minimam and only 

 exposed locally. Of one feature mention may be made, that had a 

 great influence upon the subsequent configuration of the country and 

 determination of the drainage. In the chapter on metamorphics an 

 anticlinal axis has been alluded to, running through a large portion of 

 the sedimentary formatiouL, and continuing from there eastward through 

 the Quartzite Mountains. So far as our work extended westward the 

 traces of this disturbance could be observed. The line it pursues is 

 approximately from west to east, with a number of small curves. A 

 short distance west of station 37 it was first noticed, running a little 

 northward past that station; it then makes a curve toward the south, 

 and crosses over to station 36, from there over to Cascade Creek and 

 station 31, crossing slightly to the north of it ; following the same 

 direction, it runs south of station 38, and enters the m^tamorphic area. 

 Its eastern termination seems to be lost under the trachyte, which 

 subsequently invaded the region. On its north side the Cretaceous beds 

 on the San Miguel and Eio Dolores take no part in the dips produced by 

 the elevation along the line given. Toward the west the dips produced 

 are not so steep as those farther east. It can be seen, however that 

 quite frequently the line of strongest upheaval is marked by the courses 

 of creeks, the strata dipping off on either side from them. Proceeding 

 toward thequartzites, however, this changes. Some of the highestpoints 

 of that group show their metamorphosed beds dipping off on either 

 side of the summit to the north and south. The course of the au- 

 ticlinal axis is there marked by a row of prominent peaks, prominent 

 both on account of their altitude and the steep slopes they present. 

 Throughout the entire older sedimentary area, south of the given line- 

 its effect can be recognized. Although the Cretaceous beds dip off, ap- 

 parently uniformly, in the same direction, unconformabilities were no- 

 ticed in several instances, and it is quite probable, therefore, that their 

 dip is to be explained by a gradual rising of that portion which 

 then was land, rather than to be regarded as the result of the same 

 upheaval. The fact that volcanic material at numerous places covers 

 both the metamorphic and older sedimentary strata, resting unconform- 

 able' upon them, shows that the disturbance must certainly have taken 

 place before the time of the volcanic eruptions. On the other hand, it 

 will be found that Cretaceous beds, appearing to have suffered no im- 

 mediate dislocation from the same cause, are likewise covered by vol- 

 canic rocks of the same age, so that the appearance of the latter upon 

 the surface could scarcely denote ihe extensive upheaval. Inasmuch as 

 all Ihe Carboniferous beds we have in the district have been affected 

 alike, it seems correct to conclude that the anticlinal axis in question 



