WAKREN UPHAM^ ESQ.^ ON CAUSES OF THE ICE AGE. 215 



steep continental slope at a distance of about 105 miles from 

 Sandy Hook. Its outermost twenty-five miles are a sub- 

 inarine fjord three miles wide and from 900 to 2,250 feet in 

 vertical depth measured from the crests of its banks, which 

 with the adjoining fiat area dechne from 300 to 600 feet 

 below the present sea level. The deepest sounding- m this 

 tjcrd is 2,844 feet.* 



2!j An unfinished survey by soundings off the mouth of Dela- 

 Avare Bay finds a similar valley submerged nearly 1,200 feet, 

 but not yet traced to the margin of the continental 

 plateau. 



30 Again, the United States Coast Survey and British 

 Admiralty Charts, as Spencer states, record submerged 

 fjord outlets from the Gulf of Maine, the Gulf of St. 

 Lawrence, and Hudson Bay, respectively 2,(564 feet, 3,666 

 feet, and 2,040 feet below "^sea level. The bed of the old 

 Ijaurentian river from the outer boundary of the Fishing 

 Banks to the mouth of the Saguenay, a distance of more 

 than 800 miles, is reached by soundhigs 1,878 to 1,104 feet 

 in depth. Advancing inland, the sublime Saguenay fjord 

 along an extent of about fifty miles ranges from 300 to 840 

 feet in depth below the sea level, while in some places its 

 bordering cliffs, one to one and a half miles apart, rise 

 abruptly 1,500 feet above the water.f 



31 Greenland is divided from the contiguous North American 

 continent and archipelago by a great valley of erosion, 

 Avbich is estimated from soundings and tidal records to have 

 a mean depth of 2,510 feet l)elow sea level for 680 nn'les 

 through Davis Strait ; 2,tlJ5 fett for 770 miles next nortli- 

 Avard through Baffin Bay; and 1,663 feet for the next 55 

 miles north through Smith Strait.ij: 



32 On the Facitic coast of the United States Professor Joseph 

 Le Conte has shown that the islands south of Santa Barbara 

 and Los Angeles, now separated from the mainland and 

 from each other by channels twenty to tlnrty miles wide 

 and 600 to 1,000 feet deep, were still a part of the mainland 



* A. Lindeiikohl, Report of U.S. Coast and Geodetic Surveu for 1884, 

 pp. 435-8 ; Am. Jour. Sci, iii, vol. xxix, pp. 475-480, June, 1885. James 

 D. Dana, A^n. Jour. So'., iii, vol. xl, pp. 425-437. Dec. 1890, with an 

 excellent map of the Hudson submarine valley and fjord. 



t J. W. Dawson, JVotes on the Post- Plioceiie Geoloji/ of Canada, 1872, 

 p. 41 ; The Canadian h:e Age, 1893, pp. 71-74. 



J Smithsonian Contributions to Knowledge, vol. xv, pp. 163, 164. 



