ROCKS OF THE COAST RANGES OF CALIFORNIA 485 
rock is composed of 75 per cent. of augite and secondary 
material, probably leucoxene, with a highly altered ground 
mass. 
2. Fourchite from Angel Island. (Bulletin Dept. of Geol. 
University of California, Vol. I, p. 231.) Ransome. 
3 and 4. Diabase from Pt. Bonita. (4th Bulletin Dept. of 
Geol. University of California, Vol. I, p. 106.) Ransome. 
5. Spheroidal basalt from Pt. Bonita. (4th Bulletin Dept. of 
Geol. University of California, Vol. 1, p. 106.) Ransome. 
Vin i) SVAN 
VI Pseudo- | Pseudo, IX | x 
Epidiorite- diabase diabase, Diabase, Diabase, 
Potrero Mt. St. Sulphur | Mt. Diablo | Mt. Diablo 
Helena Bank | 
SuiliGaleee teeter | terre rsync cekcr: 47.41 49.08 51.28 51.58 52.06 
PANT UITIVATL APP cae, epedctis eitavecs, sd cranetotiait 16.03 14.68 15.05 14.99 14.34 
INGIRAO OaGleras debioodorel ocood 2.66 1.95 2.41 2.04 Dao 
HETGROUSTOXIGEs spr eyeielcie: jcrieners ale 7.05 9.63 8.01 8.36 7.74 
Mined Oreos sree reueroraanet tiers uellehieris) oral eis 12.33 10.09 7.08 8.59 8.05 
IMMEWeNNSSIEN 64 46600 6900090000 5.81 6.69 6.07 6.51 9.26 
IPOLASS aM apt oa eons ) 0.20 0.12 0.31 0.73 
SOU Anas sie nts atts ceo aad 4.60 4.43 3.08 1.74 
MAWES Soules Coog oo sHo4 COON Palache | Melville | Melville | Melville | Melville 
6. Epidiorite Potrero. (Bulletin of Geol. University of Cali- 
fornia Vol: lip. 77.) ~ Palache, 
7. Pseudo-diabase from near Mt. St. Helena. (Monograph 
XIII, U. S. G. S., Becker, Quicksilver Deposits, p. 98.) 
8. Pseudo-diabase, Sulphur Bank. (Mon. XII, p. 99.) 
Becker. 
g and 10, Diabase from Mt. Diablo. (Bulletin Geol. Soc. Am., 
Voli: 412. )e  lurmer 
Serpentine —There are very abundant areas of serpentine in 
the Coast Ranges, single masses often covering many square 
miles. The occurrence of serpentine was noted by the geolo- 
gists who accompanied the Pacific Railroad exploration parties, 
and the first analysis of a California serpentine which I have 
found recorded, is that given by Professor Newberry, and is of 
a specimen collected at the Presidio at San Francisco. Later, 
