HARRISON — NOTES ON THE ORIGIN OF THE WORLD. 411 



in such a series, successively accumulated from the wearing away of 

 an original indurate mass by a primeval ocean. Since, by the above 

 theory, the primary rocks have only one source, the granite, whilst the 

 secondary have at least two, the same granite and also the compara- 

 tively soft strata of the primary deposits, from whence these several 

 materials might have been derived, — it requires but little discernment 

 to see that, allowing an equality of time for the production of each, 

 the latter ought to be immensely the greater of the two. The fact 

 is, however, the directly opposite ; whilst the tertiary, derivable from 

 three distinct sources, — to say nothing of volcanic agency during 

 this last period, — is far smaller in its development than either of the 

 aqueous formations immediately preceding. Nor is it fair to demand 

 a longer period for the accumulation of the older strata ; since the 

 earth being, in those ages, comparatively new and unsettled, it can 

 scarcely be supposed that the times of quiescence allowing deposi- 

 tions to go forward would be more extended than in the latter geo- 

 logic ages, during which the earth may be regarded as approaching a 

 state of actual repose. 



One might also reasonably expect, under the circumstances, to 

 find the water-worn materials, of which the sedimentary rocks were 

 formed, growing gradually smaller in all the latter deposits, since 

 these last must necessarily have been subjected to by far the greater 

 amount of wearing action from their frequent changes of position. 

 Here, again, facts are decidedly against the theory of primitive gra- 

 nite being the origin of the earth's sedimentary crust, — conglomerates 

 and gravels being rare in the secondary, and almost unknown in the 

 slate rocks ; whilst modern tertiary gravels, containing pebbles, and 

 even angular fragments of quartz and granite, are common in every 

 land wherein tertiary deposits are to be found at all. 



Granite, again, is believed to have been produced under immense 

 pressure, — a condition altogether irreconcilable with the idea that such 

 granite was formed as a surface rock. The weight too of granite 

 would appear to offer a most striking argument against its assump- 

 tion of so high a position upon the gradual cooling of the earth's ma- 

 terials, some of which are known to be of very trifling density. 



But even supposing the great framework of the globe to be of gra- 

 nite, still we cannot help agreeing with Mr. Jukes that the analogy 

 drawn from the phenomena observed upon the cooling of lavas and 

 other molten matter, would rather suggest the surface of recently 

 solidified earth must necessarily be covered by vast heaps of ashes, 

 scoriae, and such light materials as naturally floated above the recently 

 liquid mass below. 



Admitting the above supposition as reasonably correct, we have at 

 once an immense amount of material, likely to contain portions of 

 very many of the substances, the bulk of which sank by their supe- 

 rior gravity towards the earth's centre ; and besides, matter espe- 

 cially in a condition such as would admit of the mass being easily 

 eroded and swept away by the storms and tempests, in all probability 

 incidental to such an early period. The detritus of this material 



