BY E. M. JOHNSTON, F.L.S. 



57 



Australia. But apart from such consideration it is clear from 

 his observations that he regards the largeness of the ocean area 

 as a, factor in intensifying the horizontal pressure of its waters, 

 and thus runs counter to one of the elementary laws determiniDg 

 the horizontal pressure of fluids. When we consider this 

 limitation we can perceive how insignificant must be the influ- 

 ence of lateral pressure of ocean waters upon coast lines when 

 compared with the enormous force required to bulge the solid 

 earthinto mountain chains. Again, as regards the energy of water 

 set in motion by winds, and the currents induced by lunar and 

 solar action, it is clear that the amount and direction of such 

 forces do not harmonise so closely with the direction of the 

 lateral thrusts, which have produced those remarkable chains of 

 mountains like the Andes, that their influence should he added 

 to the supposed influence of the pressure of oceanic waters 

 already referred to. As regards the reference to Dr. Carpenter 

 I cannot see that the quotations given have any bearing upon 

 the pressure exerted by oceanic waters on their land border. 

 Indeed, Mr. Danvers-Power does not seem to be aware that 

 the last quotation referred by him to Dr. Carpenter is nearly 

 exactly word for word identical with, and, no doubt, adopted 

 from Dana's theory of the elevation of mountain chains parallel 

 to the great oceans. (Dana in p. 828, Manual of Geology, 3rd 

 edition, 1879). Dana here affirms (prior to Dr. Carpenter), 

 "The fact that the largest and loftiest mountain chains, 

 greatest volcanoes, and other results of uplifting and disrupting 

 force characterise the borders of the largest oceans, shows that 

 the shoving action from the direction of the oceans was approxi- 

 mately proportional to the ocean basins ; but Dana clearly 

 explains that this shoving motion is not due to the superficial 

 waters contained in these basins, but that " the landward action 

 of the force seems to be a necessary consequence of the fact 

 that the crust over the oceanic areas was, and is abruptly 

 depressed below the level of the continental, so that the lateral 

 pressure from its direction would have the advantage of leverage 

 beneath the continental crust, or rather would have acted 

 obliquely upward against it." There is a fundamental differ- 

 ence here between the lateral pressure of ocean water, and the 

 oblique upward lateral thrust of the ocean bed, and Dr. 

 Carpenter's quotation is in entire harmony with Dana's theory, 

 and gives no support to Mr. Dan vers- Power's ece^m ivater theory. 

 The idea originated by Archdeacon Pratt that the rocky 

 material under the ocean is more dense than that under 

 continents has also influenced Dana in ascribing greater 

 stiffness or rigidity to oceanic areas, and so determining in 

 some measure the peculiarities connected with mountain chains 

 running parallel to the great ocean. At any rate their 

 arguments in no way support the novel theory of Mr. 

 Danvers-Power. As regards the parallelism observed between 



