THE WAR IN THE OCEAN 229 



lower surface, and thin the crust. It was of such thinness 

 that the internal heat escaped with rapidity sufficient to pre- 

 vent a lowering of the temperature of the different zones of 

 crust, and thus produce a thickening of the crust. But, if 

 by sedimentation, the crust were made thicker, this balance 

 would be destroyed ; the escape of internal heat would be re- 

 tarded, and it would therefore, re-fuse the inner surface of the 

 crust, and restore the thickness, and with it, the balance of 

 actions. Thus, wherever the original crust has been supple- 

 mented by sediments, more or less of the original crust has 

 been lost from the under side. Who can say how much has 

 been lost? Undoubtedly, an amount approximating the entire 

 thickness of the overlying sediments. It is generally admitted 

 that the Eozoic strata are 50,000 feet thick. There must 

 have been consequently, 50,000 feet of the primitive crust 

 melted away. This leaves crust-thickening due to progressive 

 cooling, to be supplied by sediments above the Eozoic. If 

 the Eozoic beds extend down 30 miles, then 30 miles of 

 primitive crust are lost. If that crust was less than 30 miles 

 thick, then some part of the 30 miles melted away must have 

 been sedimentary rocks. 



I wish to make one more point in this connection, and 

 that, I believe is new. If sediments accumulated only along 

 the continental slopes, then not only did all formations grow 

 finer and thinner in receding from the shore ; but they must 

 be found to disappear at great distances from the shore ex- 

 cept in shallow water. Thus, we are not at liberty to suppose 

 the Eozoic beds extended under all the oceans, so as to be 

 literally universal. Wherever they now exist, the land was 

 then not far distant. Thus also, in general, it should result 

 that att formations grow thinner and less fragmented as they pass 

 under newer formations. 



So it appears that by due reflection, it becomes possible to 

 reproduce the important features of the ocean's primitive his- 

 tory. The earliest outcrops of sea-bottom were entirely con- 

 sumed by erosion. We find traces of those lost lands in the 

 grains of vitreous quartz, which must have been a product of 



