RECONNAISSANCE IN COLORADO AND UTAH 677 
or fine-grained granite, little modified by movement or pressure, 
and these seem plausibly to be equivalent in age to the massive 
granites of the Needle Mountains, which are later than the quartzites 
of the Uncompahgre formation referred to the Algonkian in the 
Needle Mountains and Ouray folios. 
That the Uncompahgre quartzites are also present in the West 
Creek area is indicated by two observations. In West Unaweep 
Canyon, near the west end, a patch of white quartzite, some hun- 
reds of feet in visible extent occurs on the north side of the valley 
a few hundred yards north of the road. Mr. Kay visited this 
outcrop and found it to consist of quartzite of fine, even grain, for 
the most part, if not wholly, surrounded by granite. 
Another occurrence of quartzite was discovered by Mr. Woolsey 
within the area of Permian (?) sediments very near the granite line 
on the south side of West Creek and several hundred feet above the 
stream. ‘These quartzites were surrounded and in part covered by 
the Permian (?) grits, and they apparently form a pinnacle or knoll 
which has been buried and is now again exposed by erosion. Small 
quartzite fragments were observed in the adjacent granite. 
These quartzite occurrences, of which scarcely more than notice of 
their existence can now be said, are very suggestive in the matter of the - 
correlation of the extensive Uncompahgre formation of the San Juan 
region with the still greater series of ancient quartzites in the Uinta’ 
Mountains. Both have been referred to the Algonkian and their 
similarity emphasized. The quartzites of West Creek are about 
go miles from the type locality for the Uncompahgre quartzites at 
Ouray on the north side of the San Juan Mountains, and 150 miles from 
the Uinta Mountains. They are thus so nearly intermediate as to 
add weight to the correlation suggested. 
LIST OF PUBLICATIONS CITED 
1. BoutweE tt, J. M. “Vanadium and Uranium in Southeastern Utah,” Bull. 
U.S. Geol. Surv., No. 260, 1904, p. 203. 
2. Corr, E. D. “Report upon the Extinct Vertebrata Obtained in New 
Mexico by Parties of the Expedition of 1874.” Monographs, U. S. Geog. 
and Geol. Surveys West of the tooth Meridian, Vol. IV, Pt. II. 
3- Cross, WuiTMAN. “‘Telluride Folio,’ U. S. Geol. Surv., Geol. Atlas of the 
U. S., folio 57, 1899. 
