398 SEE— THE NEW THEORY OF EARTHQUAKES [November 15, 



" The continents now rise about 3 miles above the average ocean bottom, 

 and much more than that in certain portions. Since the volume of the 

 ocean has probably not greatly changed during known geological time and 

 since the continents appear to have risen above surface, about as now, in 

 the earliest known geological ages, it is assumed that similar differences of 

 relief have prevailed at the various known deformative periods. We have 

 seen that the gravitative pressure at 3 miles' depth is nearly or quite as 

 great as the shearing-resistance at that depth. If a shearing-zone at depths 

 of 3 to 5 miles had already been developed during the primary deformation, 

 this would facilitate a reversed movement along the same shear-planes. It is 

 therefore conceived that the continental platforms, by pressing upon their 

 bases to the extent of 16,000 to 30,000 pounds to the square inch, would, 

 though opposed by perhaps 5,000 pounds per square inch pressure from the 

 oceans, gradually creep laterally under their own gravity, in a slow glacier- 

 like way. This supposed lateral creep should be attended by crevassing, As- 

 suring, and normal faulting; in other words, ^3; the prevalent tensional phe- 

 nomena which the continents present. It should be much more marked in 

 the plateau regions than elsewhere, because of their superior elevation, and 

 it is there that normal faulting is most pronounced." 



Thus in one place we are assured that the continents have been 

 squeezed up, in another that they are creeping down in a slow glacier- 

 like way. If they are creeping down how were the mountains ele- 

 vated? And why should these uplifts appear at the borders of the 

 continents? Perhaps it will be answered that these two movements 

 are going on together. But does not the first principle of the new 

 theory tell us that neither of these supposed movements has any real- 

 ity, and that the mountains and plateaus are elevated by the ex- 

 pulsion of lava from beneath the sea, the shells of which are thus 

 carried to the greatest height in the gradual uplift of the land? 



§ 17. On the Folding and Distortion of the Strata seen at the 

 Earth's Surface. — In many works on geology the crumpling and 

 folding of the strata are attributed to " a gentle warping of the 

 soil." No doubt where mere settlement of the ground is in progress, 

 owing to undermining, there is some warping of the soil; but this 

 implies that the strata have already been uplifted and undermined, 

 so as to become unstable. Such uplifting is the work of earth- 

 quakes, during past geological ages, though the settlement and warp- 

 ing may be due to the gradual undermining efifects of water or other 

 agency which produces instability. All movements of this kind 

 are of small importance compared to the greater and more violent 



