1863. J 297 [Lesley. 



tribution of the slickensides movement, taken into connection with 

 the crumpling up into subanticlinals, and the tongue-shaped crimp- 

 ling of the softer measures inside of these*, must have relieved the 

 strain upon the outside of the synclinals below and anticlinals above, 

 and set quite aside the necessity for those yawning gaps which are 

 supposed by many to have occurred along all the great anticlinal axes 

 of the region. It may be safely taken for granted, that had such oc- 

 curred on the upper side of the anticlinals, similar ones would have 

 occurred on the under sides of the synclinals, of which we see no 

 trace. That the slipping of stratum upon stratum has gone on every- 

 where is everywhere evident. The softer formations have been 

 most injured by it, and are penetrated by crumplings when the 

 harder strata have splintered and fissured. But, as a whole, the pli- 

 cating energy must have acted with a steady evenness of thrust, 

 which carried up the anticlinal waves of the crust unbroken, and in 

 some cases to a height of between five and ten miles above the pre- 

 sent surface level. 



By what agency could these masses have been removed, without 

 leaving Alpine ranges, with serrated summits and protuberant spurs ? 

 Can we imagine the Pyrenees to be reduced by ordinary atmospheric 

 erosion to the condition of the Jura ? Giving even infinite time, 

 will the desired result be ever attained ? On the other hand, given 

 a homogeneous element with suiEcient force, acting either by one or 

 by repeated blows, the result as we now see it on the present ground 

 was demonstrably certain to come from the conditions which we see 

 to have existed on the former ground. No one will deny that water, 

 if obtained in sufficient quantity at a suflBcient velocity, would be 

 such an agent. In the acknowledged instability of the crust of the 

 earth, and in its acknowledged less stability in ancient times than 

 now, we find the possibility, nay, we feel the certainty, that the 

 oceans have at times been launched across the continents, and we 

 Deed nothing more to satisfy all the conditions for an explanation of 

 Appalachian topography. 



Parts of a private letter from Leo Lesquereux, Esq., of 

 Columbus, Ohio, were read respecting the fossil botany of the 

 coal, and the publication of manuscript memoirs in prepara- 



* See Plate V for a few instances of this structure as yet unpublished. Many 

 others, even more instructive, can be obtained in our various collieries. The 

 western edge of the Broad Top basin is remarkable for the number, symmetry and 

 regular sequence of these tongues ; but they are common to all the anthracite 

 basins. Fig. 6 is an accurate representation of one ngar Beaver Meadow. 

 VOL. IX. — 2a 



