1863.] 293 ■ [Lesley. 



No. The excavation of the Appalachian surface has not been 

 determined by transverse faults; but entirely by longitudinal flex- 

 ures ; and has not been accomplished by glaciers ; nor by rain and 

 river water; still less sub oceano. By what then? I think much 

 must be discovered before the question can -be answered, if we reject 

 subaerial deluge action. What for example do we know yet of the 

 internal structure of those deep diluvions or alluvions which occur in 

 our transverse river-bottoms, where they cross the longitudinal valleys 

 of Devonian olive shale ? They seem to be ancient lakes, excavated 

 at the time the topography of the valleys and mountains was deter- 

 mined, and filled with river tra.sh. As they occur in the transverse 

 river valleys, they seem to own the rivers for progenitors. But being 

 in line with the gaps, the occupation of them by the rivers seems, on 

 the contrary, to be as fortuitous as the river-occupation of the gaps. 

 Moreover, the present rivers are evidently the degenerate representa- 

 tives of grander floods, and the silt of these depressions, judging by 

 the surface, is of too gross and hasty a nature for collection by less 

 than such original deluges. But supposing this also to be a fancy, 

 what relation does the glacial hypothesis, which presumes to annul 

 the necessity for a cataclysmic eroding agent, propose to bear to 

 parallels of latitude ? 



Wherein does the valley of the New River or Kanawha difi"er from 

 that of the Susquehanna or Delaware, except in having no New York 

 corals or Canada syenites among its pebbles. In every structural 

 feature they are alike; and like the valley of the Tennessee in Ala- 

 bama. There is no change in the height or constitution or form of 

 the mountain plateau through which they cut. There is no change 

 in the range to the southeast of them which can aff'ect the question; 

 for the Black Mountains of North Carolina, even if liable to suspi- 

 cion as glacier-bearers, are far enough removed from the New River 

 on the north, and the Tennessee on the south, to be of no account in 

 this discussion. Is the glacial hypothesis prepared to defend its 

 claims in Middle Alabama under the parallel of 33° ? If not, then 

 it has no claims to any feature of the Catskill Mountains under the 

 parallel of 43°, except their scratches; to which, so far as the gene- 

 sis of mountains and valleys is concerned, it is quite welcome. Yet 

 precisely this bonbon Professor Ramsay refuses it ; for he maintains 

 (against Dana), that the striae at the Catskill Mountain House were 

 made by icebergs floating down the Hudson estuary, and not at all 

 by glaciers. There is a disposition manifested of late among the 

 American geologists, of the New England school, to fill each of the 



