NOTE ON THE “CARBONIFEROUS OF THE SANGRE 
DEY ERISTO RANGE, COLORADO: 
THE detailed section given below was taken at the crest 
of Sangre de Cristo range, directly west of Trinidad, Colo., 
between the sources of the Middle Fork and the North Fork of 
the Purgatory River. The Sangre de Cristo range reaches a 
maximum elevation in this region of 14,079 feet, in Mt. Culebra. 
From this peak northward the crest of the range descends 
gradually to an elevation of about 9,300 feet at Veta Pass, 
thence rises again to Sierra Blanca— 14,413 feet—the highest 
peak in Colorado. 
The crest of the Sangre de Cristo range is composed for 
the most part of coarsely crystalline rock flanked by sedimen- 
taries. At the point where the section was taken the crystal- 
lines of the crest pass gradually beneath the surface, giving 
place to the sedimentary formations. From this point north- 
ward for a considerable distance the crest of the range is com- 
posed mainly of strata having a northeastward dip (see Hayden’s 
Atlas of Colorado). Mr. Endlich maps a considerable portion of 
the sediments as Lower Carboniferous; but the greater part, 
including the barren red sandstones, which are several thousand 
feet thick in this region, is mapped as Upper Carboniferous. 
The red sandstones are obviously a part of the Red Beds, whose 
wide distribution in the mountain region is well known, but 
whose age is still a matter of doubt. 
It was in the hope that some light might be oes upon 
the age of certain isolated remnants along the eastern slope of 
the mountains that I took the trip to the fossil-bearing series at 
the crest of the range. In place of the Lower Carboniferous 
series which I had expected, I found the Upper Carboniferous 
series reported in the accompanying section. This section was 
taken in a cafion near the southern limit of what Mr. Endlich 
mapped as Lower Carboniferous. To the north of this point 
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