Lawson.] 



Geology of Carmclo Bay. 



5" 



of the country, may have been the same as the great post-Miocene 

 uplift which has been so fully recognized by Whitney, Becker, Le 

 Conte and other earlier investigators. What the character of that 

 uplift was in detail we have no means of saying. Whether it was 

 a uniform, slow uplift, or a rapid and violent one, intermittent in 

 rate of movement, or whether it was a vacillating movement, uplift 

 alternating with temporary depression, we have discovered no evi- 

 dence to enable us to say. But this fact may be affirmed, that 

 when the uplift reached such a point that the land was about 265 

 feet lower than now, there was a halt, and the relations of sea and 

 land remained stationary for a time. The duration of this time is 

 measured by the work done by the San Jose in corrading its canon 

 walls till it had established a flat trench floor of granite. Then the 

 coast began to sink, and the stream detritus, coming from the high- 

 grade canons in the Santa Lucia, began to accumulate on the floor 

 of the trench, and the delta, which was formerly at the mouth of 

 the stream, began to extend up the valley. The process of sub- 

 sidence and accumulation continued till the trench floor was buried 

 beneath at least 175 feet of gravel. At this stage of the subsidence 

 the delta was wholly or partially overwhelmed by a flow of lava 

 (carmeloi'te). The same flow also mantled the granite slopes above 

 the surface of the delta. The fact that a portion of these granite 

 slopes is flat and terrace-like suggests that it had formerly been 

 terraced by the sea, probably during the earlier uplift of the coast. 

 After the outflow of lava the subsidence continued ; and, as this 

 subsidence as yet had little retarding effect upon the action of the 

 streams in the high-grade canons which drained from the lofty 

 ridges of the Santa Lucia, accumulation proceeded as before, and 

 the delta was built up upon the surface of the lava sheet, and spread 

 out over its edge. This continued till the coast was depressed to 

 at least 620 feet lower than at present. During the accumulation 

 of the delta the subsidence was probably gradual and uniform in 

 rate. In the vicinity of the mouth of San Jose Canon no evidence 

 of further depression was observed; but our 800 feet sea beach on 

 Huckleberry Hill is only four and one-half miles distant to the 

 northwest, and it seems fair to suppose that the depression which 

 this implies was reached by a continuation of the same downward 



