ANTIQUITY OP THE TERRACES. 63 



Charles Lyell as of great value in this respect; although I might suppose that his 

 views of uniformity are sometimes carried too far. The rule which I theoretically 

 adopt, is, to admit paroxysms wherever there is evidence of their action, but not 

 introduce them for the sake of eking out an hypothesis. For we ought ever to 

 remember, that in nature, uniformity is the law, and paroxysm the exception. 



I will only add, that if it be admitted that the facts adduced in this paper prove 

 the presence, since the drift period, of the ocean at the height of 2000, or even 

 1200 feet, above its present level, then it must have extended over nearly all of 

 our western country; and unless Professor Agassiz says that he had his eye upon 

 this matter along the shores of Superior, I cannot avoid entertaining the expecta- 

 tion, that what I call beaches will yet be found at a much higher level there, than 

 the 331 feet terrace, measured by Mr. Logan. 



29. The period when the formation of beaches and terraces commenced was 

 immensely remote. The proof of this position will more appropriately be given in 

 my paper on Erosions. I trust there to prove, that the whole of the gulf between 

 Niagara falls and lake Ontario has been worn out by the river since the drift 

 period : as well as the gorge between Portage and Mount Morris, on Genesee river, 

 and several analogous gulfs in other parts of the country. I expect also to show, 

 that some of the old river beds, pointed out in this paper, were beds through which 

 rivers ran before the continent went down beneath the ocean the last time. Such 

 facts, if admitted, give an antiquity to the drift period little imagined heretofore ; 

 and may excite astonishment that the drift strise should be so fresh and distinct 



30. The facts and reasonings that have been presented, exhibit to us one simple, 

 grand, and uninterrupted series of operations, by which all the changes in the 

 superficial deposits since the drift, have been produced. We see the continent 

 slowly emerging from the ocean ; rivers commencing their wearing action on the 

 islands; waves and oceanic currents meeting the detritus of rivers and comminut- 

 ing, sorting, and arranging the same, in the shape of beaches and terraces, while it 

 may be that icebergs and glaciers modified the whole. It may be, too, that 

 paroxysmal movements occasionally accelerated, retarded, or modified, the effects. 

 The period over which the uninterrupted operation of these agencies can be 

 traced, may be regarded as the alluvial, and we can refer them back at least to the 

 tertiary epoch. 



31. It is obvious, however, that it is only the present form and admixture of the 

 loose materials on the earth's surface, that can be referred to the post-tertiary period. 

 We infer that their present arrangement is post-tertiary because they lie in some 

 places above the tertiary. In others, however, they lie upon older rocks — some- 

 times upon the oldest known. And in such case, though the presumption is strong 

 that their present disposition and mixture are not older than the tertiary, yet the 

 time of the abrasion, comminution, and rounding of the fragments, may have been 

 vastly earlier — as early, indeed, as the consolidation of the rocks on which they 

 now repose. They may have formed other terraces and beaches on other conti- 

 nents ; and it is quite possible that in some cases those old terraces and beaches 

 may still remain, not having been remodelled by the last vertical movement of the 

 continents. In an important sense, therefore, the alluvial period may have been 



