228 The American Geologist. April, 1894 
GEOLOGICAL NOTES ON THE SIERRA NEVADA. 
By H. W. Turner, Washington, D. C. 
( Published by permission of the Director of the U, S. Geological Surrey.*) 
The Sierra Nevada is composed of a series of mctarnorphic 
sedimentary rocks, with which are associated large amounts of 
igneous rocks, granite, diabase, etc. On this older series of 
pre-Cretaceous age there rests with a marked unconformity a 
little. altered series of sediments, tuffs and lava-flows of late 
Cretaceous and Tertiary age. The rocks are here treated of 
under two headings; first, the sedimentary formations, and 
second, the igneous rocks. 
PART I. 
THE SEDIMENTARY FORMATIONS. 
The following formations have been recognized in the Sierra 
Nevada by the U. S. Geological Survey. The much metamor- 
phosed auriferous slate series has, however, not been satisfac- 
torily subdivided. Future discoveries will further unravel 
this complex. 
Only those formations that are known to occur to the south 
of the fortieth parallel, comprising nearly the whole range. 
are included here. For information concerning the north end 
of the range the reader is referred to the publications of Mr. 
J. S. Diller, Prof. A. Hyatt, and Prof. Whitney. The forma- 
tions are as follows: 
( !rj stalline schists 
Age ■'. 
Grizzly formation 
Silurian. 
( lalaveras formal ion 
Lower '.' Carboniferous. 
Little Grizzly beds 
Upper '.' ( larboniferous. 
Mineral King beds' 
Triassic. 
< !edar formal ion 
Triassic. 
Sailor Canyon beds 
Jura-Trias. 
M ilton scries 
Jura-Trias '.' 
Mariposa siaies 
Jurassic. 
( ihico formal ion 
1 ' pper < !re1 aceous 
Tejon formation 
Eocene. 
< )coj a ( 'reek beds 
M iocene. 
[one formal ion 
Miocene.J 
Auriferous riser gravels 
Miocene a nd Pliocene. 
Shore gravels 
Pliocene. 
Shore and river gravels, / 
lake beds and moraines \ 
Earlj Pleistocene. 
Alluvium 
Late Pleistocene. 
*These notes are in pari an abstracl of a paper that is scheduled to 
appear in the fourteenth annual reporl of the United Slates Geological 
Survev. 
