72 NEW VOKIv STATE MUSEUM 



and in the (lull' ol' Caiic lliclon. oil" liie Cote des Landes, France, 

 in such relations to siiltmarine currents as to favor the hypothesis 

 that these cliaimcls ai-c unfilled j;ortions of the coastal plain kept 

 oi)en by currents w liidi prevent deposition along the line of these 

 gorges. ^Vhat st^^nis to be to some writers an \iiiansweral)le 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 l)egan to form that the rivers flowing through 

 the lakes have by u])lift of the lake bottom been enabled to dissect 

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

 tion of the outer i)art 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 topogi*aphy 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 iimd as compared with the tempera- 

 ture of the lakes. hi 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.^ 



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

 gorge no facts have herotofoi*e been observed on the neighboring 

 land wliicli (it'iiiand in i>ostglacial times so high an elevation of 

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

 gorge. The dcjdli of tlic bed rock in the Hudson river between 

 New ^'<•rk city and llic Highlands would be, if known, a much 



'For litcraturo on the subject consult Suess, La Face de la Terre, v.2, 

 1000, p.8r..3-r)(;, with references to papere by Lindenkohl, J. D. Dana, 

 G. I)avl<lson. I-\ A. l^^orel, Eberhard Craf Z<>ppolin, Duparc, Delebec*que 

 aud others. 



