Lawsun ] 



Geology of Carmelo Bay. 



53 



of the San Jose and the valley of Carmelo River, at an elevation of 

 470 feet. These borings are only about ten or twenty feet above 

 the base of the steep revetment which terminates (just within the 

 limits of our map) the ridge which separates the Carmelo from the 

 San Jose. This steep hill, thus squarely truncating the ridge, is, 

 therefore, with little question, to be interpreted as a sea cliff. The 

 steepness and sharpness of the cliff evidence how little the insoluble 

 Monterey shale has yielded to atmospheric erosion since this strand 

 was abandoned by the sea. 



Another very well-defined shore line is about 300 feet above 

 tide. This also may be seen in the form of a terrace cut out of 

 Monterey shale on the main road descending to Carmelo Bay. 

 The terrace is, as in the last case, covered with a thin formation of 

 cemented bowlders and pebbles, with some coarse sandstone. The 

 water courses have in many places cut through the terrace forma- 

 tion, and show it reposing upon the worn edges of the inclined 

 Monterey shale. In this, as in all the other terrace formations, 

 fragments of this shale abound. The same strand is represented 

 on the Monterey side of the wind gap, on the coast road, by very 

 abundant borings at an altitude of 300 feet. Borings are also well 

 shown on the same part of the road at about 200 feet. Another 

 very well-marked strand, both on the slopes of Monterey and those 

 of Carmelo Bay, has an elevation of 150 to 160 feet. Below this 

 are various, more or less distinct evidences of former shore lines, 

 but the only set of these which can be signalized as very well 

 defined and persistent is that at from twenty-five to thirty feet above 

 tide. At this altitude are broad wave-cut terraces and stream ter- 

 races, which seem to mark a prolonged constancy of the relation of 

 sea and land. On Carmelo Point there is also a terrace fairly well 

 defined at about fifty feet above the tide. 



As the uplift of the coast proceeded, the streams purged their 

 valleys of delta material, and lowered their trenches into the under- 

 lying rock. In this process they did not always recover their old 

 trenches. This was the case with the San Jose. We have seen 

 that after its old trench was choked with the accumulating delta it 

 was at its lower part covered with a lava sheet. This obstruction 

 seems to have prevented the stream from resuming its old-time 



