Proceedings of the British Association. 363 



te?ied, would occupy a much greater space than at present ; and 

 the area of the Alps and Jura would be greatly extended if all 

 their contortions were spread out. The phenomena described in 

 the Appalachian chain, so far as small differences in the direction 

 of the anticlinals were concerned, did not at all affect the brilliant 

 theory proposed by M. Eiie de Beaumont ; the object of the ge- 

 ologist was to trace the correspondence in the direction of the 

 great lines of elevation, and in this broad view the northeast and 

 southwest direction of great part of the European rocks agreed 

 remarkably with the direction of the Appalachian chain. He 

 did not consider the pulsation of molten matter, as described by 

 the authors of the paper, necessary to account for the flexures so 

 very numerous in the strata of mountainous districts, but not 

 confined to them, and in many instances unaccompanied by the 

 intrusion of igneous rocks. The only force necessary for the 

 production of such flexures and contortions was, the tangential 

 or lateral pressure, in order to compress the strata into a smaller 

 space. Contortions were formerly accounted for by a supposed 

 secular diminution in the volume of the earth ; the crust was 

 compelled to accommodate itself to the diminished surface arising 

 from the contraction of the mass. But it was to be remembered, 

 that these contortions were not common to all the world ; in 

 Russia the strata presented one even bend over a wide area. Our 

 knowledge of America, and much of the rest of the world, was 

 imperfect, and until we were much better acquainted with the dis- 

 tribution and character of contorted strata all over the globe, we 

 should not be able to account very rationally for the figures they 

 assumed. Mr. Sedgwick pointed out those circumstances in the 

 structure of the Appalachian chain which accorded with previous 

 observations in Europe ; the persistency of the strike of the strata, 

 the parallelism of the anticlinal and synclinal lines, and the dimi- 

 nution in the amount of disturbance as the strata recede from the 

 district where the greatest force was applied. He did not allow 

 that the circumstance of curvilinear elevations was opposed to the 

 theory of M. Beaumont, who had himself described curved ele- 

 vations quite as striking. Most of the instances adduced by Prof. 

 Rogers, in illustration of his view of the average inclination of 

 the strata being greater on the side of each flexure farthest from 

 the centre of the disturbing forces, did not in his opinion confirm 

 the view the authors had taken of the origin of those contortions. 



