BRITISH ASSOCIATION. 



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N.E. and S.W. direction of great part of the European 

 rocks agreed remarkably with the direction of the Appala- 

 chian 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 pres- 

 sure, in order to compress the strata into a smaller space. 

 Contortions were formerly accounted for by a supposed se- 

 cular 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 distribution 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 pre- 

 vious observations in Europe ; the persistency of the strike 

 of the strata, the parallelism of the anticlinal and synclinal 

 lines, and the diminution in the amount of disturbance as 

 the strata recede from the district where the greatest force 

 was appHed. He did not allow that the circumstance of cur- 

 vilinear elevations was opposed to the theory of Mr. Beau- 

 mont, who had himself described curved elevations quite as 

 striking. Most of the instances adduced by Prof. Rogers, in 

 illustration of his view of the average incHnation of the strata 

 being greater on the side of each flexure farthest from the 



