PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 599 



since it would tlirow no light upon the forms, number, and 

 arrangement of the continents. But when the true theory of the 

 ocean currents comes to be understood, the fact of the distribution 

 of the sediment, and th^ depressions produced by its weight, 

 assumes vast importance. If it is objected that I cannot directly 

 prove that elevations are produced in this manner, and that there- 

 fore the idea is a mere conjecture — I answer, that it is true we 

 cannot see the lava moving beneath the pressure of the ocean's 

 floor, and therefore it may be said that the geonomic theory does 

 not admit of direct occular proof; but, at the same time, to a phi- 

 losophical mind, the evidence is of such a nature as to be quite as 

 irresistible as occular demonstration. Herschell quotes from Lord 

 Bacon, the observation that "the confirmation of theories relies 

 on the compact adaptation of their parts, by which, like those of 

 an arch or dome, they mutually sustain each other, and form a 

 coherent whole." When we consider what a vast number and 

 variety of facts are accounted for by the geonomic theory and by 

 no other, while not a single known fjict can be found opposing it, 

 our minds are so constituted that we cannot resist the conviction 

 that it must be true. 



Sources of the Sediment. 



It is supposed by some authors that the ocean currents do not 

 abrade the bottom of the deep sea ; and therefore, it may be 

 objected to the geonomic theory that, whe»i the ocean covered the 

 whole earth, there could not have been enough sediment collected 

 to cause the depression of the earth's crust by its weight. It 

 must, however, be considered, that the ocean contains an abun- 

 dance of other materials for sediment besides those obtained by 

 the mechanical abrasion of its floor. The limestone formations, 

 some of them several miles in thickness, are composed, almost 

 entirely, of the organic remains of creatures that have lived and 

 died in the ocean. If it be admitted that a very small quantity of 

 chemico-vital sediment annually settled upon the bed of tire primi- 

 tive sea, geology steps in with its countless ages, and magnifies 

 the total amount to more than enough for all the purposes of our 

 theory. 



Prof. Phillips, in his Manual of Geology, 1859, London edition, 

 p. 633, remarks: "Nothing is more certain than that of all the 



• As Boon as an ocean washed the consoUdatcd crust of the globe, it would begin to 

 abrade the surfaces upon which it moved, gradually loosening and detaching the materials 

 to cepoeit them again. — Agassiz^ Geological Sketches, 



