W. B. Taylor — Crumpling of the Earth's Crust. 257 



He says : "As we look at the whole series of changes from the 

 remote past, the ellipticity of figure of the earth must have 

 been continually diminishing, and thus the polar regions must 

 have been ever rising, and the equatorial ones falling ; but as 

 the ocean always followed these changes they might quite well 

 have left no geological traces. The tides must have been 

 very much more frequent and much larger, and accordingly 

 the rate of oceanic denudation much accelerated. The more 

 rapid alternations of day and night would probably lead to 

 more sudden and violent storms, and the increased rotation of 

 the earth would augment the violence of the trade winds, 

 which in their turn would affect oceanic currents. Thus there 

 would result an acceleration of geological action."* 



In this suggestive retrospect one important physical condi- 

 tion, however — which probably has " left its geological traces " 

 on our globe — does not appear to have attracted the author's 

 attention. A shell formed upon the spinning earth when its 

 oblateness was considerably greater than at present obviously 

 could not fit the spheroid as the ellipticity of its meridians 

 diminished. Not only would the crust be quite sensibly too 

 large, as a whole, but especially would its equatorial girth have 

 to be notably reduced. 



If in imagination we may carry back the formation of a con- 

 sistent crust (of some few miles thickness) to an epoch when 

 the rotation of our planet was at four times its present rate — 

 that is, when the day measured but six of our hours, — the equa- 

 torial radius (assuming a true ellipsoid of revolution, and 

 neglecting the small amount of contraction by loss of heat), 

 would have been about one-tenth greater than it now is, or 

 4359 miles ; and the polar radius about one-sixth less, or 3291 

 miles. In other words, the poles would have been about 658 

 miles nearer the center of the earth than they are at present, 

 and the equatorial protuberance about 396 miles higher than at 

 present. 



With an equatorial shell one-tenth greater in circumference 

 than the present dimensions, it is evident that from the very 

 slow but never ceasing contraction due to diminution of rota- 

 tory motion, this crust would be subject to an unremitting 

 stress of lateral compression as relentless as that from the old 

 hypothetic shrinkage of volume by reduction of temperature. 

 Is it not precisely this morphologic contraction whose effects 

 and records are everywhere apparent in the crumpling of the 

 earth's crust? Here is a true cause : here is a sufficient cause : 

 here is a necessary cause — so importunate that it cannot readily 

 be dispensed with or explained away. 



An objection to this hypothesis, based on the supposed 

 * Phil. Trans. Roy. Soc, December 19, 1878, vol. clxx, p. 532. 



