250 IT. B. Taylor — Crumpling of the Earth's Crust. 



Conte, and others, that the tangential stresses of secular lateral 

 compression have resulted in very great differences of thicken- 

 ing in the crust, deepening simultaneously the foundations of 

 the mountains as they were slowly protruded upward, while 

 leaving the great depressions proportionately attenuated, so 

 that the internal topography of the shell is an obverse corre- 

 sponding closely with its external contours, — although an 

 hypothesis framed for the avoidance of supposed hydrostatical 

 difficulties in the conception of a layer of approximately uniform 

 thickness, floating on the liquid abyss, — is yet on both geo- 

 logical and physical grounds exposed to at least as weighty 

 objections. 



It is proposed in this communication to consider only the 

 probable origin of that great contraction of the terrestrial 

 crust so widely manifested in its plications or crumplings, in- 

 creasingly marked as we approach the great oceans. 



The liquidity of our globe, and the relative thinness of its 

 incrusted envelope, — as attested by all legitimate geological in- 

 duction, — will be assumed without misgiving or hesitancy; 

 and the supposed mathematical arguments for its solidity — 

 ignored as essentially fallacious and wholly inconclusive. It 

 must be lamented that the professional mathematicians have as 

 yet contributed nothing to the advancement or to the exten- 

 sion of geologic theory : — not from lack of analytic skill in a 

 Thomson, or a Darwin, but from the want of proper data to 

 justify the conclusions they have so boldly hazarded. 



On the universal recognition from numerous evidences that 

 our earth is a cooling globe, still highly heated within, the 

 suggestion by Elie de Beaumont, in 1830, that " the inequality 

 of cooling [between the interior and exterior portions] would 

 place the crusts under the necessit}^ of continually diminishing 

 their capacities ... in order that they should not cease to 

 embrace their internal masses exactly," and that this condition 

 "may with great probability completely account for the ridges 

 and protuberances which have been formed on the external 

 crust of the earth :"* — this seemed so natural and obvious an 

 explanation, that it commanded a very general assent among 

 geologists.f 



*Phil. Mag., Oct., 1831. vol. x, pp. 263, 264. 



f " Elie de Beaumont and some other geologists have attributed these effects 

 and especially the elevation of mountains to the contraction of a cooling globe, 

 and this appears to be the only one adequate for the results. ... In attributing 

 the plications of the earth's crust and the elevation of most mountains to a lateral 

 pushing movement within the crust, there is nothing hypothetical. The state- 

 ment is the expression simply of a fact. The conclusion that this tension [com- 

 pression] is due to the contraction of a cooling globe has not yet been fully 

 established. It is here adopted, because no other that is at all adequate has 

 been presented." — Prof. J. D. Dana, Manual of Geology, 1863, part iv, chap, vi, 

 sect. 1, pp. 721 and 725. 



