120 SOUTHWESTERN NEVADA AND EASTERN CALIFORNIA. 
ness of 4.000 feet of stratified rocks is exposed from a point 2 miles 
southwest of Belted Peak westward to the detrital deposits mantling 
the range. The section contains no important stratigraphic break, 
and while shales and quartzites are interbedded, limestone is the pre- 
dominant rock. The limestone is typically fine grained, crystalline, 
and dark gray or black in color. The bedding planes are as a rule 
massive. Thinner beds of a yellow or brown, more coarsely crystal- 
line limc-tonc are also present, and a single stratum of oolitic lime- 
stone was observed. Entraformational conglomerates and cross-bed^ 
ding, each an indication of shallow-water deposition, occur through- 
out the section. Nodules and fewer lenses of black chert are present 
in places. The nodules are in part original, but since the bedding 
plane- in certain instances cut them, they are also in part secondary. 
A related phenomenon is the silicification of certain beds of lime- 
stone to a compact, conchoidally fracturing black jasperoid. The 
lime-tone- are cut in all directions by veinlets of coarsely crystalline 
white calcite, and these were evidently formed at several distinct 
periods, since they cut and. in places, fault one- another. 
Quartzite forms a prominent bed near the middle of the Poo-onip 
limestone, and in many place- -hale and quartzite beds are laminated 
with lime-tone near the top of the -cries. The quartzite is usually 
light in color and fine grained, although some beds are stained red by 
hematite and others are medium grained. Quartz veinlet- with 
crystal-lined vugs cut the quartzite. Much of the quartzite is argil] 
laceous and grades into slaty -hides, which are thin bedded, fine 
grained, and. as a rule, olive green in color, although locally black or 
brown. Muscovite films are developed on the parting plane- of both 
the -hale- and the more argillaceous quartzh 
This sedimentary series was evidently laid down in ;i sea of mod- 
erate depth which at time- was -hallow. The condition- were on the 
whole favorable to the deposition of lime-tone, although at intervals 
line fragmental material was carried into that portion of the ancient 
-ea now occupied by the Belted Range. This lime-; oik- closely resemj 
bles the Pogonip linn-tone of the Panamint Range, although from 
cat thickness it may extend well down into the Cambrian. Mr. 
E. (). Ulrich identified, from material collected by the writer, Giri 
vanella-\ike form- of smaller size and denser structure than tho-e 
collected from the Cambrian lime-tone of the Si her Peak Range. 
He considers these probably of Ordovician age. 
Weber conglomerate. — The Weber conglomerate forms the crest 
and eastern slope of the Belted Range south of Whiterock Spring. 
as well as broad ridges west of Oak- Spring and north of Whiterock 
Spring. The formation includes a sand-tone from 800 to 1,000 feet 
thick and an overlying shale from 300 to .V><> feet thick. While 
sandstone predominates in one member and -hale in the other, soma 
