GEOLOGIC RECONNAISSANCE IN BAJA CALIFORNIA 725 
Lindgren’ has given considerable information regarding schist 
and granite in the northern part of the peninsula; Gabb? noted 
some features observed on his trip north from La Paz; and Emmons 
and Merrill’ described relations of the schists near the onyx quarries 
east of Santa Caterina. 
I obtained no evidence as to the age of these granites and 
schists, but my general impression was that they were much older 
than Cretaceous. I did not observe any overlap by Cretaceous rocks, 
but I saw Tertiary deposits lying on or against them at various 
places. In the region east of La Paz, the granite appears to be 
the floor on which the Tertiary volcanic series lies. This relation 
is strongly indicated at Cabo Lobos on the east side of Isla Espiritu 
Santo where a separating fault appears hardly possible. A similar 
relation is indicated in Sierra Giganta, northwest of Loreto. The 
structural relations of the ridges of schists in Isla Santa Margarita 
and extending northward to Cabo San Lazaro is not known, and 
it is not unlikely that these rocks are the uplifted floor of the strata 
farther east. 
CRETACEOUS SYSTEM 
General relations—A large part of the peninsula is underlain 
by Cretaceous rocks which outcrop extensively in the central and 
northern parts. ‘Two principal series are present, both of late 
Cretaceous age and separated by an uncomformity, the older 
series, of unknown correlation, having been uplifted, flexed, and 
cut by large igneous masses before the younger series, Chico, was 
deposited. ‘The Chico beds were not observed in contact with the 
‘older series, and the principal evidence of the separateness of the 
two is the difference in attitude of the beds throughout the area 
and the fact that the older series is uncomformably overlapped by / 
t Lindgren, ‘‘ Notes on the Geology of Baja California, Mexico,” Proc. Cal. Acad. 
Sth, Second Series, Vol. I (1889), pp. 173-96, and Vol. II (1890), pp. 1-17; and 
“Geology and Petrography of Baja California, Mexico,” Proc. Cal. Acad. Sci., Second 
Series, Vol. III (1890), p. 26. 
2 W. B. Gabb, Geol. Survey of Cal.: Reports, Vol II (1869), Appendix, pp. 1-20. 
3S. F. Emmons and G. P. Merrill, “Geological Sketch of Lower California,” 
Bull. Geol. Soc. An., Vol. V (1894), pp. 489-514. 
