214 Mr. T. M. Reade on the Geological Consequences of a 



hypothesis are tending to corrugate the surface of the globe, 

 subaerial denudation is, pari passu, levelling all the irregu- 

 larities that appear above the waters of the ocean, and sedi- 

 mentation in varying degrees at different localities is more 

 or less effacing the irregularities below the waters. 



It would be an interesting calculation to approximately 

 work out the relative magritudes of these opposite actions, 

 but such is not my present inter tion. It will be more to the 

 purpose to enquire whether such a process — deductively ar- 

 rived at — is in correspondence with what takes place in nature. 

 The geological standpoint is an entirely different one to that 

 of the deductive reasoner. The geologist is prepared to 

 question any physical dogma otherwise called a " law," no 

 matter how high the authority on which it may stand, if obser- 

 vation leads him in an opposite direction. It is, however, in 

 this branch of enquiry by the application of the two methods, 

 the inductive and the deductive and their correspondence, 

 that the most important and far-reaching truths are eventually 

 discovered. 



I can quite understand a contractionist, in view of the dis- 

 covery of the level-of-no-strain, giving up the position that 

 mountain-ranges have originated in the shell-of-compression, 

 yet contending that the other irregularities of the earth's 

 surface have originated in the differential movements of the 

 underlying contracting shell. He would probably point to 

 such a persistence of movement of subsidence, though only 

 deductively arrived at, as another proof of the permanence of 

 oceans and continents. 



When, however, as geologists we go to Mother Earth and 

 ask her to yield up her secrets, what does she answer ? 



It seems pretty safe to assert anything of the abysmal 

 depths of the ocean, for we know little of the ocean-bottom 

 excepting what is yielded by a few scrapings of the dredge 

 and the number of fathoms read off on the sounding-line. 

 When, however, we investigate that which is more within 

 our reach, we find that everywhere on the globe there has 

 been in progress a constant flux and reflux of elevation and 

 subsidence, and it would be difficult to say which has been, 

 on the whole, of the greater magnitude. It is but lately that 

 Dr. Guppy has shown us that there are on the Solomon 

 Islands soft foraminiferous rocks which, according to Murray 

 and Brady, represent deep-sea deposits laid down in water 

 from 1800 to 2000 fathoms deep. These deposits in many 

 cases lie upon old denuded volcanic rocks, and are overlain 

 with a capping of hard coral rock. 



These deep-sea rocks are, in the case of Ugi and Treasury 



