174 REPORTS ON INVESTIGATIONS AND PROJECTS. 



atomic, and subatomic activities, including the radioactive, as might 

 arise under the conditions of the case. The presumption is there- 

 fore strong that the temperature would be very high in the central 

 portions and would decline systematically toward the surface, and 

 hence the secular effects of thermal changes would embrace not 

 simply the loss of heat from the surface but the transference of heat 

 from greater to less depths. The heterogeneous association of matter 

 throughout the globe resulting from the postulated accretion must 

 have given rise to great possibilities of recombination and rearrange- 

 ment under heat and pressure in the interest of maximum density, 

 and hence the hypothesis postulates such rearrangement and recom- 

 bination as one of the potential factors in the deformation of the 

 earth in the course of its history. As such rearrangement of mate- 

 rial may have taken place at all depths, it is obvious that the problem 

 of deformation under this hypothesis must take into consideration 

 possible deformative agencies working throughout the entire globe. 

 The redistribution of the heat by internal transference also involves 

 this conception (Tear Book No. 3, pp. 238-244). The deformative 

 agencies, under the assumption of a molten globe, have, on the other 

 hand, usually been regarded as essentially superficial, and hence the 

 new system must be worked out on its own lines. 



Reasons were set forth in my last report (Year Book No. 3, pp. 

 244-247) for believing that the water-covered areas of the growing 

 earth, after it had acquired a hydrosphere, would develop a higher 

 specific gravity than the land areas, due to differential weathering, 

 and that these heavier water-covered segments would therefore 

 take precedence in each great deformative movement in the interest 

 of greater density. Not only would they take precedence in time, 

 but in the amount of depression. If the deformations of the earth 

 were limited merely to the protrusion of the continental platforms 

 and to the depression of the oceanic basins, the dynamical explanation 

 might rest with the differentiating effects incident to weathering on 

 the land and hydrospheric protection under the water throughout 

 the long process of growth ; but the surface of the earth is still further 

 differentiated by plateaus, anti-plateaus, and folded mountains, as 

 as well as the minor phenomena of faulted blocks, warped surfaces, 

 etc. Some of these clearly imply compressive lateral movements, 

 while others as clearly imply crustal tension. The problem, there- 

 fore, embraces not only the massive shrinkage concerned in the 

 formation of abysmal basins and continental platforms, but the 

 accessory compressive actions involved in folded mountains and over- 

 thrust faults and the contrasted tensional actions implied by normal 

 aults, gaping fissures, and other relaxative phenomena. 



