THE HISTORY OF THE NORTH ATLANTIC 'Jl 



mountain and plain, already begun ; and of these we may more 

 especially note the continued subsidence of the areas of 

 greatest marine deposition. This has long attracted attention, 

 and affords very convincing evidence of the connection of sedi- 

 mentary deposit as a cause with the subsidence of the crust.^ 



We are indebted to a French physicist, M. Faye, for an impor- 

 tant suggestion on this subject. It is that the sediment accu- 

 mulated along the shores of the ocean presented an obstacle 

 to radiation, and consequently to cooling of the crust, while 

 the ocean floor, unprotected and unweighted, and constantly 

 bathed with currents of cold water having great power of con- 

 vection of heat, would be more rapidly cooled, and so would 

 become thicker and stronger. This suggestion is complemen- 

 tary to the theory of Professor Hall, that the areas of greatest 

 deposit on the margins of the ocean are necessarily those of 

 greatest folding and consequent elevation. We have thus a 

 hard, thick, resisting ocean bottom, which, as it settles down to- 

 ward the interior, under the influence of gravity, squeezes 

 upwards and folds and plicates all the soft sediments deposited 

 on its edges. The Atlantic area is almost an unbroken cake 

 of this kind. The Pacific area has cracked in many places, 

 allowing the interior fluid matter to exude in volcanic ejec- 

 tions. 



It may be said that all this supposes a permanent continu- 

 ance of the ocean basins, whereas many geologists postulate a 

 mid-Atlantic continent to give the thick masses of detritus 

 found in the older formations both in Eastern America and 

 Western Europe, and which thin off in proceeding into the 



^ T>w\X.on'\x\. Report oj U.S. Geological Survey, 1 89 1. From facts stated 

 in this report and in my "Acadian Geology," it is apparent that in the 

 Western States and in the coalfields of Novia Scotia, sliallow-water deposits 

 have been laid down, up to thicknesses of 10,000 to 20,000 feet in connection 

 with continuous subsidence. See also a paper by Ricketts in the Geol, 

 Mag., 1883. 



