354 The American Geologist. Bhs 
by a lava flow near the site of Tick canyon, and dessicated by 
the heat of the sun, resulting in the precipitation of the gyp- 
sum in layers interbedded with layers of mud. 
Fast of Tick canyon there is a layer of hard gray limestone, 
several hundred yards long and in places 18 inches thick, in- 
ter-bedded with the volcanic rock. The limestone and gypsum 
are evidences’ of a marine origin for the detrital portion of 
the series. I failed to find a trace of fossils, but the volcanic 
activity and resulting gases passing into solution in the sea- 
water may have been inimical to life on that portion of the sea 
bottom. 
The series is everywhere well lithified and even the sand- 
stones outcrop readily. Dr. H. W. Fairbanks secured some 
fine photographs of the craggy sandstones near Soledad canyon, 
but he paid no further attention to the formation. Its pres- 
ervation is due to the protective influence of the hard lava 
sheets and to its having been faulted down into the crystalline 
complex. Fragments of it are met in the higher mountains 
in most unexpected places. 
Between a range of gneiss mountains at the head of Tick 
canyon and the high schist ridge of the Sierra Pelona, a belt of 
granite is overlaid by a dull dark red (making buff hills) 
breccia and breccia-conglomerate, passing upward into well- 
stratified conglomerate and coarse sandstone. The series is 
well lithified, is mostly of granitic material, shows none of the 
neighboring lava, stands at a high angle, dips southerly, oc- 
cupies a belt 2000 to 3000 feet wide and has an estimated 
thickness of 1500 feet. It extends for miles toward the west- 
southwest down Texas canyon and its presence has given rise 
to a basin or broad valley probably one mile in average width, 
connecting on the east with a broad basin at the head of Mint 
creek. On the south side it is faulted to an extent of in 
places probably 1500 or 2000 feet. Another remnant faulted 
down into the older rocks is cut by the west fork of Mint 
canyon. These remnants of a great and perhaps wide-spread 
basal breccia conglomerate I correlate with the basal conglom- 
erate of the lava and sandstone series of Tick canyon, and 
with the basal breccia-conglomerate under the lava near the 
head of Fscondido canyon. It must be recognized as a distinct 
