352 The American Geologist. Jane, 1895 
in immediate contact with them. Gradations may often be 
observed from the most crystalline of these schists into the 
normal sandstones and volcanic rocks of the series. The in- 
ference is unavoidable that the schists are the local zones of 
contact metamor]:)hism due to the intrusion of the irruptive 
rocks. The extremely irregular distribution of the intensity 
of the metamorphosing action in these contact zones is very 
perplexing and makes the field study tedious in the extreme. 
But when the irregularity is recognized as a constant factor 
in the problem, the study is simplified. The association of 
glaucophaue, or hornblende, or mica schists with intrusive pe- 
ridotites and other basic irruptives, is, in the experience of 
the writer, constant through the Coast ranges. The best il- 
lustration of this association is afforded by Angel island, 
which has been thoroughly investigated by Mr. Ransome.* 
There can be no reasonable doubt but that the sporadic oc- 
currences of schists throughout the Coast ranges in rocks 
similar to those of the San Francisco peninsula are but local 
contact zones. In a recent trip on horseback through the heart 
of the northern Coast ranges from Humboldt county to the 
Golden Gate, the writer saw this relation of schist and irrup- 
tive so repeatedly exemplified that he advances the h^^pothe- 
sis with the greatest confidence. 
Correlation of the Franciscan Series. — The correlation of 
the Franciscan series cannot at present be satisfactorily set- 
tled. The paleontological evidence bearing on the question is 
as follows: (l)The occurrence of Inoceramus in the San 
Francisco sandstone of Alcatraz island as recorded by Whit- 
ney. (2) The discovery of a fragment of a shell, which, ac- 
cording to Mr. Stanton of the U. S. G. S., is either an Inoce- 
ranius or an Ancella, in the same formation south of San 
Mateo. (8) The occurrence at the base of the series on the 
flanks of Montara mountain of shells which Mr. Stanton has 
determined as probably belonging to Pectunculus and OjJis, 
and others which resemble more recent species of Venus. 
(4) The Foraminifera of the foraminiferal limestone embrace, 
according to Mr. Charles Schuchert, the genera Orhulina, Glob- 
igerina, Textularia and Jiofalin, and in the opinion of Prof. 
Walcott the association of forms indicates an association of 
*Loc. cit. 
