726 N. H. DARTON 
the Eocene strata which lie with apparent conformity on the Chico 
beds. This relation is shown in the following section (Fig. 5). 
These pre-Chico Cretaceous rocks consist of conglomerates, 
quartzites, tuffs, and agglomerates with large bodies of inter- 
bedded eruptive rocks. They are also cut by dikes and large 
stocks of igneous rocks of vari- 
ous kinds. In many localities 
theigneous rocks predominate 
over the sediments or pyroclas- 
Frc. 5.—Sketch section showing rela- .. és F 
tions of Eocene and Chico beds to meta- tics, and in places there is much 
morphic and igneous rocks of Cretaceous metamorphism. Unaltered or 
(pre-Chico) age, near latitude 30°, west but little altered sandstone and 
coast, Baja California. a, exposed overlap 4 
aes oo shales appear in places, notably 
near old San Domingo Mission, 
25 miles north of San Quintin, where they contain many large 
oyster shells, and in the Arroyo San José, 40 miles southeast of 
Santa Caterina. Limestone alsooccurs. It is conspicious north and 
northeast of the ruins of Mission San Fernando, 30 miles due east 
of Rosario, where the relations shown in the following sketch section 
(Fig. 6) are presented. The limestone is filled with fossil oysters of 
upper Cretaceous age. Part of the outcrop is shown in Figure 7. 
These metamorphic Cretaceous rocks appear to extend as far 
south as latitude 28° 40’, and possibly the schists and other rocks, 
Fic. 6.—Sketch section showing relations of Cretaceous limestone north of the 
ruins of San Fernando Mission, 30 miles east of Rosario, Baja California. 
although apparently of an older series and extending to Calmalli, 
may be metamorphosed Cretaceous sediments. Apparently they 
are so regarded by Bosé and Wittish in their brief statements 
regarding relations in the Northern District. 
*“Memoria de la Comisién del Instituto Geolégico de México que exploré la 
regién Norte de la Baja California,” Inst. Geol. de México, Perergones, Vol. XIV (1913) 
PP. 397-533- 
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