92 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



are here 1,000 feet high. A third branch heads into the 

 northeast angle of the bay, but the 25-fathom curve reaches 

 in only half a mile from the shore. Between these two 

 heads enters the Carmel River from the SE., but it is too 

 weak and insignificant to suggest the submerged valley. 



The few characteristic specimens of the bottom show 

 green mud and sand at 100 fathoms on the south plateau; 

 fine green mud and mica on the north plateau, and green 

 mud, sand and mica at 475 fathoms. 



Northward of Point Cypress the soundings decrease, and 

 from Point Pinos the plateau of Monterey Bay stretches for 

 thirty miles to the NW. 



The latest soundings with the dredge show boulders under 

 the soft muddy bottom at 480 fathoms off Point Pinos. 



16. The Monterey Plateau and Submerged Valley. 



Monterey Bay is a great bight or gulf extending about 15 

 miles inside the general trend of the coast, and is about 23 

 miles wide. 



From the general conditions of the San Francisco plateau 

 to the northward, and the low country to the eastward, we 

 would naturally expect the loo-fathom plateau to occupy the 

 whole of the gulf or bay. Nevertheless, a remarkable sub- 

 merged valley, similar to that of Point Hueneme, runs across 

 this plateau and heads into a low-lying country immediately 

 behind the 30 miles of shore-line of Monterey Bay. It 

 reaches into the middle of this low line of beach near the 

 mouth of the Salinas River, and the 50-fathom line is within 

 less than half a mile of the shore. 



The valley, which runs east and west, is narrow, and at seven 

 miles from the shore the lOO-fathom curves are only two miles 

 apart and the depth 350 fathoms where the 50-fathom would 

 be normal. It broadens, and at 11 miles has a depth of 615 

 fathoms. From its nothern edge a short, deep valley reaches 

 to the northeast, but the 50-fathom curve of this arm is five 

 miles from the shore. 



The characteristic soundings adjacent to this valley are 



