164 KEPOET UNITED STATES GEOLOGICAL SURVEY 



below the great bend, and just above the point where it turns again to 

 the northwest. From this bend we crossed to the head of Parados 

 Valley, down which we followed a few miles ; thence we travelled south- 

 ward across the Basin Plateau, and a little southwest across Gypsum 

 Valle> and Saucer Yalley to the Dolores. Returning, we crossed the 

 head of Gypsum Valley, and, skirting the country near the northern 

 slopes of Lone Cone, turned north to the crossing of the San Miguel, 

 having completed the circuit of the area. 



Four days' travel from the Uncompahgre Indian'agency, on the Un- 

 compahgre River, brought us into our northern district (area B). The 

 southern line of this area is Grand River, which, after it is joined by the 

 Gunnison, curves around the northern end of the Uncompahgre Plateau, 

 flowing at first northwest and afterward southwest. In this area the 

 geological formations extend uninterruptedly Irom the Red Beds (Trias'?) 

 exposed on the Grand, to the Tertiary strata outcropping at the summit 

 of the "Roan" or "Book Cliffs." 



Grand River is, for the most part, in a low caiion in the Red Beds. 

 On the north side, the Dakota sandstones, with the underlying shales form 

 low hogbacks, dipping away from the river toward the cliffs. Between 

 the crest of the hogbacks and the foot of the cliffs is a broad valley, 

 formed by the erosion of the soft shales of the Middle Cretaceous. Tbese 

 shales extend to the base of the cliffs, and in some places form their 

 lower portion. The cliffs rise in steps to the summit, which has an ele- 

 vation of 8,900 to 9,000, rising about 4,000 feet above the level of Grand 

 River. The summit of the cliffs is the southern edge of a plateau, sIod- 

 lug northward to White River (Dr. Eudlich's district). The strata in 

 the cliffs are Tertiary sandstones and shales, through which the streams 

 flowing to White River rarely cut deep enough to expose the Cretaceous. 



Our line of travel through this district was as follows : 



Crossing the Grand on the wagon-ford above* the mouth of the Gun- 

 nison, we followed the road (wbich keeps on the north side of the river) 

 nearly to the mouth of the Dolores. We then crossed the Grand River 

 Valley to where Desert Creek emerges from the clifl's. From this point 

 we followed the Indian trail, which leads up the western branch, to the 

 summit of the cliff's. We then turned eastward on the trail, which fol- 

 lows the crest of the divide between the Grand River and White River 

 drainage, leaving it at the head of Roan Creek. This latter stream was 

 followed to the Grand, up which we travelled to Cactus Valley. 



With this our work ended, the northern portion having taken twenty- 

 three days to complete. The area included is about 3,000 square miles, 

 while area A included only about 1,000 square miles. 



From Cactus Valley we proceeded to Rawlins Springs, on the Union 

 Pacific Railroad, via the White River Indian agency. 



We reached Rawlins on October 23, having been in the field just two 

 months, nearly half the time being occupied in marching to and from 

 and between our districts, on account of their remoteness from settle- 

 ments. 



