ransome] CARNOTITE AND ASSOCIATED MINERALS. 11 
line. The primary object of the expedition, in accordance with a 
suggestion from Mr. S. F. Emmons, was to investigate the copper 
deposits of La Sal Creek, Paradox and Sinbad valleys, and the vicinity, 
which had been' the occasion of some mining excitement a few months 
before. A memorandum from Dr. W. F. Hillebrand, received just 
before starting, indicated that it would be well also to examine certain 
prospects on which some preliminary work had been done, looking 
toward the extraction of ores of uranium and vanadium. It is to these 
ores that the present notes are confined. 
The most convenient way of reaching Paradox Valley was found to 
be the stage road, which, starting from Placerville, a settlement and 
station on the Rio Grande Southern Railroad, runs by way of Nor- 
wood, Shenandoah, and Naturita to Paradox, a distance of 00 or 70 
miles. The region can also be reached from the west by way of 
Moab, in Utah. 
The topography of the region west of Placerville is that character- 
istic of the "mesa country" of western Colorado and southeastern 
Utah. Broad stretches of plateau are intersected by steep-walled 
canyons and cliff -encircled valleys. The underlying rocks comprise the 
Red Beds" of the Dolores formation" (Triassic), the La Plata forma- 
tion (Jurassic), the McElmo formation (Jurassic), the Dakota sand- 
stone (Cretaceous), and the Mancos shales (Cretaceous). Carbonif- 
erous rocks occur in Sinbad Valley, and a series of gypsum-bearing 
shales of unknown age is found in the bottoms of Sinbad and Paradox 
valleys, but as the ore deposits to be described all occur in the beds of 
the La Plata and McElmo formations, these older rocks need not again 
jbe referred to % The sediments making up these various formations 
lie usually nearly horizontal, but they are sometimes flexed and fre- 
quently faulted. 
In all of the prospects examined the ore of uranium occurs in the 
form' of the recently described bright-yellow carnotite. In one case 
this is intimately associated with a dull olive-green mineral which, 
according to Doctor Hillebrand, is either identical with, or very closely 
tullied to, the vanadium-mica roscoelite. Deposits of one or both of 
(these minerals occur widely scattered over San Miguel and Montrose 
bounties, Colo., and in the Blue Mountain (Sierra Abajo) district of 
southeastern Utah; but only a few of the known deposits were per- 
sonally examined. 
PLACERVILLE DEPOSITS. 
These are essentially vanadium deposits, and occur 4,500 feet nearly 
northeast of the railway station near Placerville, and about 1,000 feel 
above the San Miguel River. The lower 900 feet of the San Miguel 
«The formation names used in these notes are those adopted by Mr. Whitman Cross in the text of 
he Telluride folio (folio 57), of the U. S. Geological Survey. The reader is referred to this folio for 
uller descriptions. 
