Geol— Vol. I.] DAVIDSON—SUBMERGED VALLEYS. 95 



to 75 fathoms. At greater depths the bottom is green mud, 

 and blue mud at some soundings on the north plateau. 



The mountain toward which this valley heads is King 

 Peak, 4,265 feet high, and only two and a half miles inside 

 the shore. The topography indicates no break in the com- 

 pact rocky coast-line, although there are numerous short 

 gulches, as in adjacent parts of the coast. 



The 25-fathom head of the valley is in latitude 40*^ 06 >^'' 

 north, longitude 124° 08' west. 



19. The Spanish Flat Submerged Valley. 



This is the second of the four submerged valleys between 

 Point Delgada and Cape Mendocino. It is only six miles 

 northwestward of the King Peak submerged valley. We find 

 that the loo-fathom plateau has decreased in width to a scant 

 five miles, and the head of the valley does not reach nearer 

 than one and three-fourths miles from the cliffs ; nevertheless , 

 it is deep and sharply defined, and has the same general 

 direction as the King Peak; that is, northeast and south- 

 west. Its length as exposed is nearly five miles, because the 

 soundings reach out only to 337 fathoms. The 300-fathom 

 curve reaches into the line of the normal lOO-fathom curve 

 and the sides have steep slopes. It heads towards the com- 

 pact bold coast-line near Spanish Flat, behind which low, 

 narrow strip the mountains rise to about 3,000 feet in two 

 miles. The plateau has a bottom of fine gray sand to 50 

 fathoms, with blue and black mud on the margins of the 

 valley; generally green mud soundings and one " rocky " 

 in the depths. 



The geographical position of the head of the valley at 

 25 fathoms is: 



Latitude 40^^ 10' north, longitude 124° 15 >^' west. 



20. The Punta Gorda or Mattole Submerged 



Valley. 



Punta Gorda, in latitude 40° 15^' north, is the bpld and 

 abrupt termination of the high, narrow mountainous ridge 



