25 



Alluvium 20 feet. 



Sandstone infusorial clays, 4 feet. 



Sandstone and calcareous slate, 13 feet. 



Bituminous shales, 60 to 80 feet. 





Dark sand and clay. 

 Sea. 



At the bottom of the cliffs and near the sea level the drainage from the strata 

 above is observable, and where water is not seen to issue there are unmistake- 

 able evidences of its presence in the growth of plants requiring much moisture 

 for their propagation even within a few feet of the sea. 



From the above section it will be seen that the bituminous slates, from a heavy 

 underlying bed to all the strata above, and though apparently firm and compact 

 in texture they admit the percolation of water, probably between the lines of 

 stratification. The freedom with which water issues from beneath these rocks 

 is best observed about one and a half miles east of the town of San Pedro, on the 

 beach ; here the waters come up through the sands of the beach in the same 

 manner as is observed in small bubbling springs situated in soft wet lands. 

 From the appearance of these plains it is evident that the dip of the coast stra 

 ta assumes nearly a level position and reversed inclination at the distance of 

 seven or eight miles east of San Pedro and towards Los Angeles, and that the 

 edges of the reversed dips, are covered by the superincumbent drifts from the 

 primitive mountains west and north of the city and plains. 



Among the sandstones, clay and slates of this district, are to be found large 

 quantities of marine mollusca in the fossil state, they are usually found in alter 

 nating beds, at times upon the summits of the cliffs among the fine alluvium and 

 soil, as in the high table ridge west of the town of Santa Barbara, or resting in 

 soft and indurated calcareous sandstone in the same vicinity. Again they are found 

 in the firm sub-soil or upon the left shores of the estero from one to three miles 

 northeast of San Pedro, in beds ranging from a few inches to several feet in 

 thickness. The bituminous slates with a few exceptions contain no fossils of ma 

 rine origin; there are occasionally impressions of fucoids to be met with, on the 

 surfaces of the lamina composing the group, and although other organic forms 

 are almost entirely absent this fact is sufficient to prove that they have had their 

 origin beneath the waters of the ocean. 



The great extent of territory which these shales cover is rather a novel as 

 well as an interesting feature in the geology of this State. They manifest them 

 selves first in quantities which entitle them to consideration as a distinct forma 

 tion, in the upper parts of the counties of Santa Clara and Santa Cruz, extend 

 ing into the county of Monterey ; the district is small however when compared 

 with that which we find further south, and appears continuous for a long distance. 

 The southern group is found to commence in the county of Luis Obispo arid tra 

 verses the whole of the west portion of that county and extends through the 

 entire length of the counties of Santa Barbara and Los Angeles, evidently un^ 

 derlying the greater part of their territory from the mountains to the sea. To 

 4 



