Oscillations of the CUtlifornia Coast. — Fairbanks. 227 
land appear to consist according to Mr. Voy of the Miocene and 
contain numerous characteristic fossils of that period. Above 
this is the great body of volcanic material, flow tuffs, etc. Mr. 
Voy's description is not clear in regard to the relative ages of 
the volcanic and Pliocene, but it would seem that the lavas, in 
part, at least, overlaid the Pliocene. The latter formation is 
widely distributed over the island and very fossiliferous. At 
various points along the bluffs on the northwest side the Pleis- 
tocene deposits appear 20 to 50 feet above the water and 
consist of clay and gravel. The Pleistocene also covers much 
of the island, overljnng the volcanic. The bluff's are 100 to 
200 feet high, and in the clay at various points, as well as in 
the little ravines on the surface, are numerous bones of the 
mammoth (E. primegenius), but all in an exceedingly poor 
state of preservation. Mr. Voy thinks there are Iwo species 
represented. They occur 20 feet above the Pliocene and 100 
feet below the surface. The specimens brought away are very 
fragmentary, but are to be seen in the Museum of the Cali- 
fornia State Mining Bureau. The first specimen from tliis 
locality, a tooth, was obtained by a Mr, Blunt in 1871. 
Dr. Yates* gives a long list of Pliocene fossils from San 
Nicholas island. He also mentions the occurrence of pebbles 
of quartzite, porphyry and talcose rocks. Similar ones are 
also found on Santa Rosa island. The pebbles in the recent 
formations on these islands indicate shallow water condi- 
tions. The Miocene sandstones and shallow water fauna 
also point to a land area in this region during that period. 
The fact that the Pliocene rests unconformably upon the 
older rocks shows the existence there of an interval of sub- 
aerial erosion similar to that following the Miocene upon the 
mainland. The islands were undoubtedly largely submerged 
during the Pliocene. Then an elevation took ])lace with a 
tilting of the Pliocene and resulting erosion. The vertebrate 
remains occurring near the base of the Pleistocene point to 
the fact that the subsidence took place following the death of 
the animals. There seems to be every reason for correlating 
this depression with that recognized in the terrace deposits 
of the mainland. 
The beds of mammoth bones is such conclusive proof of a 
*IXth Report of the Cal. State Min. Bureau, p. 58. 
