324 Doubts Relative to the Epochal and 



certain that between the epochs of these revolutions the 

 state of the earth was not extremely dissimilar to that which 

 we now behold ; yet, because the organic beings preserved 

 in the earth in each of these systems are peculiar to it, and 

 differ from the others and from those that now live, we 

 cannot possibly doubt that the points of difference are nume- 

 rous, general, and important." 



The same writer thus speaks of the tertiary periods : " In 

 general, no contrast can be more complete than that between 

 the secondary and the tertiary stratified rocks ; the former 

 retaining so much uniformity of character, even for enormous 

 distances, as to appear like the effect of one determined 

 sequence of general physical agencies ; the latter exhibiting 

 an almost boundless variety and relations to the present con- 

 figuration of the land and sea not be mistaken. The organic 

 bodies of the secondary strata are obviously and completely 

 distinct from those of the modern land and sea; but in the 

 tertiary deposits it is the resemblance between fossil and 

 recent kinds of shells, corals, plants, &c., which first arrest 

 the judgment." 



If, then, it is granted that the same physical agencies 

 were at work from the commencement of the tertiary period 

 to the present time, and therefore that the known phenomena 

 occurring along our rivers, lakes, shores, and deltas, or oceanic 

 estuaries, were the same then as now, and also that the 

 effect of the trituration of the water on the sides and at the 

 bottoms of rivers was then as it is now, and that at the time 

 of the commencement of the tertiary period the greater part 

 of the earth's surface was covered with secondary rock for- 

 mations, how is that tertiary formations do not abound in 

 the organic products washed down by, and precipitated from, 

 the waters that have flowed over, say, oolite or Jurassic, 

 the Wealden or chalk formations, or, not to be par- 

 ticular to a shade, say from the coal beds of the car- 



