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NEW YORK STATE MUSEUM 



and in the Gulf of Cape Breton, off the Cote des Landes, France, 

 in such relations to submarine currents as to favor the hypothesis 

 that these channels are unfilled portions of the coastal plain kept 

 open by currents which prevent deposition along the line of these 

 gorges. What seems to be to some writers an unanswerable con- 

 firmation of this view is the well marked gorge traversing the delta 

 of the Rhone in Lake Geneva and that of the Rhine in Lake Con- 

 stance. In the case of these lakes it is impossible to assume since 

 the modern deltas began to form that the rivers flowing through 

 the lakes have by uplift of the lake bottom been enabled to dissect 

 their deltas ; it is more reasonable to suppose that the configura- 

 tion of the outer part of the delta in each case is due to causes now 

 in action. Forel notes that the amount of sediment carried out 

 over the bottom at the mouths of these rivers is too great, and 

 that the process has been carried on for too long a time to permit 

 any antecedent topography to remain. In his opinion these " sub- 

 lacustrine ravines " are the result of erosion now going on and 

 prove the existence of currents in the bottom of the lakes. He 

 attributes the excavation to the lower temperatures of the river 

 water charged with mud as compared with the tempera- 

 ture of the lakes. In the case of the Congo submarine 

 channel, Buchanan has noted the occurrence of a lower, inflowing 

 salt current in the river preventing in its course the deposition of 

 sediment. Suess claims that in this case it is not so much that 

 the canyon has been excavated as that the sediments have been 

 laid down either side of it, thus building up the continental shelf 

 and leaving a gorge in the path of the inward moving, bottom 

 current of sea water. 1 



It must be admitted that in the case of the submarine Hudson 

 gorge no facts have heretofore been observed on the neighboring 

 land which demand in postglacial times so high an elevation of 

 the coast as does the gorge itself when regarded as a true river-cut 

 gorge. The depth of the bed rock in the Hudson river between 

 Xew York city and the Highlands would be, if known, a much 



1 For literature on the subject consult Suess. La Face de la Terre, v. 2. 

 1900, p.853-56, with references to papers by Lindenkohl. J. D. Dana, 

 G. Davidson, F. A. Forel, Eberhard Graf Zeppelin, Duparc, DelebeCque 

 and others. 



