282 Cincinnati Society of Natural History. 



2. Middle Miocene, consisting of grits and calcareous sandstones, as 

 at Panza and Santa Margarita. Thickness, 360 feet. And the San 

 Antonia sandstones with Dosinia. Thickness, 250 feet. 



3. Lower Miocene, consisting of the gypseous and ferruginous 

 sandstones of Santa Inez, Panza, and Gavilan, containing Ostrea^ 

 and Turritella. Thickness, 1,200 feet. Total thickness of the 

 Miocene, 2,211 feet, but part of this has since been referred to Eocene 

 age. 



He supposed that the elcA'ation of the Coast Eange, in California, 

 above the water level, was an event much later in time than that of the 

 Sierra Nevada. During the Eocene period, the latter range must 

 have had its crest considerabh^ above water, and was uplifted, finally, 

 after the Miocene period ; but it is probable that during the whole of 

 the Miocene period, the Coast Range was altogether beneath the sea 

 level. Anterior to the Post-pliocene period, the erupted rock tilted up 

 their strata, which, perhaps, did not reach the level of the ocean sur- 

 face, and upon these smoothed edges, were deposited the unconsoli- 

 dated clays and local drift. The}' had not, however, fully appeared 

 above the surface of the ocean until the close of the Post-pliocene 

 period. The elevated sea beaches found distributed over so large an 

 extent of country, from north to south, at a level of from 100 to 150 

 feet above the sea, and containing species, all of which are now exist- 

 ing, show how comparatively recent is the final elevation of the lower 

 lands of the State, and places the time of elevation of this range in the 

 earh' portion of the Post-pliocene period. The plutonic rocks of the 

 coast hills, also attest the comparative newness of the land ; pumice, 

 obsidian, felspathic lava, trachyte, amygdaloidal greenstone, and ser- 

 pentine. Volcanic rocks, of the latest kind, are choye which are com- 

 monly distributed both in the form of axes and veins, or seams. 

 Granite is also found, though not so extensive as a disturbing agent, 

 or an elevator of a mountain ridge. When found in place, it is an 

 older rock than those above mentioned, being cut through and in- 

 jected b}^ them, in many places ; but the granite, in the Coast Moun- 

 tains, is a modern granite, being either highly felspathic, passing into 

 Jeucite, and even trachj'te in many places, or it is hornblendic, and 

 passes into a hornblende porph^-r}^ ; micaceous granite is very spar- 

 ingly distributed in Southern California. The elevation of the Coast 

 Range must have taken place from two points, one in the north, and 

 one in the south ; the latter force commencing in the southern part ol 

 San Luis Obispo, and the eastern part of Santa Barbara counties, and 

 thence extending north ; as the upheaving force passed northward. 



