72 The American Geologist. February, 1893 
tegval i)ortion of the Metamorphic series. This determines the 
relative ages of the two formations; and if it is a fact, as I be- 
lieve it to be, that this granite is identical in age with that form- 
ing the great mass of the Sierra Nevada, the Metamorphic rocks 
into which it has been intruded belong to the same series and 
were uplifted at the same time as those of the Sierra. The time 
of this convulsion is supposed to have terminated the Jurassic, 
and to have been followed b}' the lowest undoubted Cretaceous 
rocks on the Pacific coast. 
The Santa Lucia range which begins at point Finos, Monterey 
county, and extends down the coast in a southeast direction, 
consists almost wholly for a distance of sixty miles of a coarse 
and somewhat porphyritic granite. Near the head of the Naci- 
mento river, the main southerly prolongation of the range changes 
its character, the granite being replaced by rocks of the pre-Cre- 
taceous series. This change is not abrupt, the massive rocks 
giving place to gneiss and schists, and these to metamorphosed 
slates, sandstones and jaspers. Owing to the extensive develop- 
ment of the Miocene sandstone on the eastern slope of the range 
the complete transition could not be seen. The granite does not 
terminate here but bears awaj' from the ocean, and crops in 
several places in a line of low Tertiary hills which extends south- 
east between the Nacimento and San Antonio rivers. The third 
of these outcrops lies near the town of Paso Robles. In line 
with these exposures and about twelve miles in a southeast direc- 
tion, granite appears again in the San Jose range. This range 
has an elevation of nearlj'^ three thousand feet and a length of 
thirt}' miles. No Metamorphic rocks appear, and near the head 
of Carisa creek the granite again sinks beneath the Tertiary. A 
high ridge of Tertiary hills connects the San Jose range with the 
San Emedio mountains, but as far as my observations have gone, 
the granitic rocks do not outcrop again until the latter mountains 
are reached. Blake, however, in the Pacific Railroad report 
maps the granite as almost continuous. Inasmuch as the several 
outcrops of this almost buried granite ridge lie directly in line 
with the course of the San Emedio range, and its prolongation 
both southeast and northwest, it seems highly probable that the 
two are reall}^ connected underneath the Tertiary. 
The Santa Lucia range follows the coast until near the town of 
San Luis Obisix), when it in turn passes inland, becoming wholly 
