Detrital Theory of Geology. 323 



laws of nature or of physics generally, the tertiary formation 

 assimilated itself in every respect to those laws now binding 

 and governing the structure and mechanism of organic and 

 inorganic matter. 



That this general inference will be admitted no reasonable 

 doubt can be entertained, since the laborious and masterly 

 work, " The Principles of Geology," by Sir C. Lyell, has 

 been so long and favourably received, not only by British 

 geologists, but by their Continental and Transatlantic 

 brethren. That able author has laboured to show that the 

 entire series of sedimentary rocks need no other forces for 

 their production than those now existing and in constant 

 operation, providing that the birthright of TIME can be 

 sufficiently extended so as to reach back to the limits of 

 their first genesis. 



The same subject is somewhat cautiously but very com- 

 prehensively summed up by the writer of the article 

 "Geology," in the "English Cyclopaedia." He thus writes : 

 " Successive phases of the aqueous and igneous agencies 

 over the same region appear, either contemporaneously or 

 successively, to have affected all parts of the earth's surface 

 accessible to man ; so that everywhere there is proof of 

 great revolutions in the condition of land and sea. More- 

 over, it appears that to each general system of stratified 

 rocks, indicative of a corresponding great system of physical 

 agencies, peculiar races of plants and animals belong ; with 

 new physical conditions new forms of life came on the globe, 

 vanished with those conditions, and gave place to others 

 equally transitory. If, now, we compare the modern survey 

 of nature with any similar work, executed on the same 

 principle, for any one of the earlier epochs, it is certain that 

 the earth has undergone many very extensive revolutions 

 in all that respects its aqueous, igneous, and organic 

 phenomena, before arriving at its present state; it is equally 



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