THE 
JOURNAL OF GEOLOGY 
NOVEMBER-DECEMBER, 18597 
hit GEOUOGleReLATIONS OF THE MARTINEZ 
GROUPOM CAEIBORNIA AT THE Twerrcak 
LOCA LIA 
THE term ‘“ Martinez Group” was first used by W. M. Gabb 
in his classification of the Cretaceous of California, the group 
of strata provisionally so designated being considered by him 
as standing between the Chico of his Cretaceous A and his Tejon 
or Cretaceous B. The Martinez was said to be of small geograph- 
ical extent and to bear such a relation to the Chico that future 
investigation might show it to be a part of that group. About 
sixty species were listed by Gabb from the group, most of them 
having been collected near the town of Martinez, in Contra Costa 
county. 
For a number of years after the publication of the second 
volume of Gabb’s work on the paleontology of California, the 
Martinez group was scarcely mentioned in geological literature, 
probably because, as described by him, it was not well under- 
stood. However as the Cretaceous B or Tejon came to be 
generally considered as Eocene the importance of the group, as 
a possible connecting link between the Chico-Cretaceous and 
the Tejon-Eocene, became evident. 
See Rep. Geol. Surv. of Cal. Paleontology, Vol. II, p. 13 of Preface. Gabb 
divided his Californian Cretaceous into a lower division, A, including the Shasta, 
Chico, and Martinez (?), and an upper division, B, or the Tejon. His Cretaceous B 
is now generally regarded as Eocene. 
VoL. V, No. 8. 767 
