Geological Notes on the Sierra Nevada. — Turner. !>45 
will) the conglomerate contains some imperfed planl remains, so thai 
fossils may yd be found to determine the age. The beds arc presumed 
to be Carboniferous in age from being apparently the continuation of 
the scries northeast of Pent/. P. ().. in the limestone of which Carbonif- 
erous fossils have been found. 
Pre- Triassic land. As was noted under "Cedar formation," 
there is on Rush creek in Plumas county a bed of conglomer- 
ate interbedded with slates and limestone, the latter contain- 
ing Triassic fossils. The writer visited this locality in company 
with Mr. Diller, who has in charge the geological mapping of 
the district. Quite a collection of the pebbles was made, and 
by permission of Mr. Diller the writer has examined a few of 
these. Quartz-diorite, diabase, and what is probably a dial- 
lage-olivine rock are represented. These pebbles will be 
studied further later. 
The pre- Mariposa upheaval. As was noted by Mr. Becker,* 
the Triassic rocks at Mineral King are enclosed in granite 
giving evidence of a post-Triassic upheaval. The pre-Mari- 
posa disturbance, of which the evidence is herewith briefly 
presented, may be identical with that which resulted in the 
upheaval and metainorphism of the Mineral King beds, but it 
is likewise possible that the Mineral King disturbance should 
be correlated with the post-Mariposa upheaval. 
The pre-Mariposa upheaval, or. to speak more explicitly, theevidence 
of i he unconformity of the Mariposa formal ion on the Cala\ eras forma- 
tion, is shown by I he following facts: First, the lithologic differences of 
the two formal ions, t he Mariposa beds consisting uniformly of black 
clay slates, which contain locally thru layers of diabase-tuff and some 
conglomerate, while I he Calaveras formal ion is made up of a variety of 
rocks, clay slaics. quartzite, phthanite, and lenses of limestone. Second, 
the occurrence of a conglomerate in the Mariposa slaics that is largeh 
made up of phthanite pebbles, precisely like the phthanite of the Cala- 
veras formation. Some of this conglomerate ma;\ be seen at the south 
base of Hear mountain, to the easl of the Texas ranch fossil locality. 
Third, in the occurrence of a narrow streak of the .Mariposa slaics cut- 
ting across the Calaveras formation, with a slight diversity in strike. 
This narrow belt of slate extends from i he Texas ranch fossil locality, 
which lies io the south wesl of Hear mountain, northwesterly across the 
Calaveras formation, crossing the road from Milton to Angel's, one mile 
sout hca si of ( 'a nn an peak. The same phthanite conglomerate thai oc- 
curs near the Texas ranch is found with the slate where ii is crossed i>\ 
the mad mentioned above-. Fourth, the paleontologic break, the Cala- 
veras formation representing the Carboniferous and probably the Lower 
•Hull. (tool. Sue. vol. 2. I). 20(5. 
