SCIENTIFIC EXPEDITION TO NORTHWESTERN COLORADO III 



The lakes in the upper valleys, as usual in glaciated mountain regions, 

 are of two types — rock basin and morainal — but some at lower levels 

 are "ox-bows" left by the cutting through of river bends. The glacial 

 topography has been since modified but little by erosion in the upper 

 parts of the valleys. 



The coal-beds of the Mesa Verde formation are numerous and exten- 

 sive and aggregate great thickness. The outcrops along the Grand 

 Hogback are easily accessible and have been worked in many places for 

 local consumption, more extensively at Meeker and Newcastle. The 

 coal is now on fire in places near Newcastle, and it seems to have been 

 of frequent occurrence in the past, as much sandstone and clay has 

 been metamorphosed from this cause along the Grand Hogback. Much 

 work has been done upon the geology of this coal-field by the United 

 States Geological Survey, reports of which work are cited in the bibliog- 

 raphy accompanying the present report. No coal is found here below 

 the Mesa Verde. 



There is much lime and clay in the region, some of which is of eco- 

 nomic value, but neither has been much exploited and apparently the best 

 has not usually been selected. Large deposits of gypsum occur in the 

 earlier formations of the upper White River Valley, reminding one 

 forcibly of the Lykins deposits east of the Front Range. Lack of 

 transportation facilities at present prevents any just estimate of its 

 value or future possibilities. Building stone is everywhere abundant, 

 some of it of excellent quality. 



Carnotite from Coal Creek, northeast of Meeker, furnished by Mr. 

 J. L. Riland, was tested by Mr. C. J. Marvin by use of sensitized plate, 

 and after an exposure of sixty hours showed very faint radio-activity. 

 The deposits have been described by Gale. 1 



Specimens of gilsonite were obtained from J. L. Riland and W. B. 

 Blythe, collected on Piceance Creek, southwest of Meeker, where it is 

 said to occur in considerable quantities. Unexpected difficulties have 

 been encountered, which have prevented complete analyses up to the 

 present writing, but incomplete analyses show that the Riland samples 

 run on an average approximately 77 per cent, carbon and 11 . 5 per cent. 



1 Gale, Hoyt S., U. S. Geol. Surv. Bull., No. 315, pp. 110-17, 1906. 



