670 



SCIENCE. 



|JS. iS Vol. XV No. 382. 



Washington could acquire such knowledge, 

 lluch can be done by cooperation, so long as 

 this does not degenerate into invidious com- 

 petition; but the autonomy and initiative of 

 the stations are assuredly the best means of 

 maintaining their usefulness to the people 

 of their several states, and to the progress of 

 agricultural science in its widest sense, viz., 

 its application to the actually existing condi- 

 tions, even though these may appear 'abnor- 

 mal' to the dwellers in the temperate humid 

 regions where that science has been first de- 

 veloped. E. W. HiLGARD. 



Univeesitt of Calitoknia, 

 March 24, 1902. 



THE SUBMARINE VALLEYS OF THE CALIFORNIA 

 COAST. 



In Science for January 10, Professor Wm. 

 E. Eitter, reporting the dredging work done 

 last simimer off the coast of southern Califor- 

 nia, states that 'the bottom deposits of some, 

 at least,' of the submarine valleys which char- 

 acterize the California coast, 'even at a dis- 

 tance of several miles from shore, are of a 

 character to prove that close inshore material 

 is carried into them in large quantities.' And 

 to him this 'observation suggests, though of 

 course does not prove, that the valleys are 

 natural channels through which currents flow, 

 at times, at least, from the shore out to deeper 

 water.' 



On entirely different grounds, the present 

 writer had reached a somewhat similar con- 

 clusion — that the majority of the submarine 

 channels of the California coast have been 

 formed, or are at least kept open, by some 

 cause now in operation, and that cause coastal 

 currents. These views and the reasons for 

 them were given by the writer in a paper read 

 before a meeting of some members of the IT. 

 S. Geological Survey, about a year ago; they 

 can be only briefly outlined here. 



The mature Coast Ranges of California, 

 t»ken as a whole, lie close to and parallel with 

 the coast line, and the coastal topography is 

 therefore rugged. As the larger stream courses 

 follow the trend of the ranges and the coast 

 for long distances, there are few coastal breaks 

 of importance. Fringing this rugged coast 



and the coastal islands is a narrow submarine 

 terrace or platform, the 'continental shelf,' 

 which has been formed mainly by marine 

 abrasion, and whose outer margin is marked 

 approximately by the 100-fathom submarine 

 contour. Its width ranges from a minimum 

 of about a mile to a maximum of about thirty- 

 two miles, the average being between five and 

 ten miles. The submarine valleys (of which 

 between twenty-five and thirty have been de- 

 scribed along the Pacific coast of California 

 and Lower California) notch this terrace and 

 its outer escarpment. The valleys, for the 

 most part, begin at or near the shore line and 

 continue to depths ranging from about 400 

 feet to more than 3,000 feet, the majority de- 

 scending to at least 2,000 feet. Most of the 

 valleys follow a course roughly at right angles 

 to the shore. Their forms are both simple and 

 branched. Some of them head opposite the 

 mouths of large valleys on the land, and some 

 opposite abrupt and rugged portions of the 

 coast, where there is no break in the Coast 

 Ranges. The valleys in general are quite 

 open, none of them being 'chasm,' as is fre- 

 quently supposed. This may be easily seen in 

 the cross sections of the valleys. While the 

 general slope of their walls differs consider- 

 ably, in any given case it is comparatively 

 gentle, taken as a whole. Two eases of un- 

 usual steepness have an angle of only about 

 20°, while the maximum angle measured was 

 about 31°, in Cape Mendocino valley. The 

 grade (profile) of the valleys is considerably 

 greater than that of the lower parts of the 

 larger coastal valleys. Vineente valley, from 

 the shore line to a depth of 1,800 feet, has an 

 average grade of about 260 feet to the mile, 

 while the grade for the first quarter-mile from 

 shore is about 720 feet to the mile. 



Two explanations of these submarine val- 

 leys have been proposed: one that they are 

 structural in origin (Lawson) ; the other that 

 they are submerged stream valleys (Le Conte, 

 Fairbanlis, Davidson). 



There can be little doubt that some of the 

 valleys are due to coastal deformation; but 

 this interpretation is unsatisfactory in ac- 

 counting for the majority of them, for the fol- 

 lowing reasons : 



