562 



SCIENCE. 



[N. S. Vol. VII. No. 173. 



SUBMERGED VALLEYS OX THE CALIFORNIA 

 COAST. 



A PRELIMINARY paper of 1886 is now fol- 

 lowed by a more detailed account of tlie 

 ' Submerged Vallej's of the Coast of Cali- 

 fornia, U. S. A., and of Lower California, 

 Mexico,' by George Davidson (Proc. Cal. 

 Acad. Sci., 3 Ser., Geol., I., 1897, 73-103). 

 Along our Pacific coast the continent de- 

 scends to depths of 2,000 to 2,700 fathoms 

 within fifty miles from the shore line. 

 There is generally a ten-mile platform slop- 

 ing out to the 100-fathom contour, after 

 which the descent is relatively sharp. The 

 edge of this platform is broken by twenty- 

 seven ' submerged valleys,' finely illustra- 

 ted in nine plates where all soundings are 

 shown, so that one may measure the ac- 

 curacy of the interpolated contours and be 

 convinced not only that the platform is 

 sharply notched where the submerged val- 

 leys are drawn, but also that it is essen- 

 tially continuous elsewhere. The notches 

 are sometimes in line with rivers on 

 the land, as at Monterey and Carmel, but 

 others appear to be entirely independent of 

 existing drainage, as King peak and San 

 Pablo valleys, both of which have to be 

 named after mountains opposite their 

 heads. The curious story is told of a 

 vessel that was lost on the rocky coast 

 fronting King peak ; she probably had run 

 in along the axis of the submerged valley 

 and, finding no bottom with the ordinary 

 line, thought she was at a safe distance off 

 shore. 



The possibility that certain chasm-like 

 valleys, such as that of Vincente, result 

 from dislocations appears to be excluded 

 by the evenness of the littoral platform on 

 either side of tlie chasm, but the actual 

 origin of the valleys can hardly be found 

 until they are studied in connection with 

 the structure, form and drainage of the 

 neighboring and still visible land. It is 

 well to guard against the implication that 



submerged valleys result from ' continentaF 

 movements, by remembering that the earth's 

 crust may bend beneath the sea as well as 

 upon the land and that the down-bending 

 and consequent submergence of a coastal 

 belt gives no more warrant of a truly ' con- 

 tinental ' movement than does the occur- 

 rence of a local inland anticline. 



WATER RESOURCES OF INDIANA AND OHIO. 



Under the above title, F. Leverett, for a^ 

 number of years engaged on the study of 

 drift deposits in the Ohio Valley, contrib- 

 utes an account of local water suppliesv 

 with particular reference to the occurrence- 

 of ground water in drift and rock (18th 

 Ann. Rep., U. S. G. S., Pt. IV., 421-559). 

 The essay includes much that is pertinent- 

 to these notes, and particular reference 

 should be made to three maps that give 

 sketch contours, rock geology and glacial 

 features of the two States concerned. The 

 last of the three is the best presentation yet 

 published of the marvellouslj^ complex drift 

 deposits formed by the great ice lobe from 

 the Erie trough. Nothing could mor& 

 forciblj^ illustrate the importance of in- 

 cluding some explanatory account of geo- 

 graphical features in the ordinary teaching 

 of geography than the contrasts here 

 brought forward between different areas, 

 according as they have been glaciated or 

 not, or as they are sheeted with the older 

 loess-covered till, the more recent moraine- 

 belted till, or the still younger lake silts. 

 The control of preglacial topography by 

 rock structure and the effect of this topog- 

 raph}' on the advance of the ice sheets are 

 well exposed ; the Bellefonte Devonian out- 

 lier, and the Scioto and Miami groups of 

 lobate moraines on either side of it, being 

 manifest illustrations. The hilly uplands or 

 'knobs' of southern Indiana, determined by 

 outcrops of the lower Carboniferous series, 

 seem to have exerted a similar control over 

 the extent of the earlier ice advance ; buti 



