VI. OF THE FLOOD TIDE. 13 



it has been described for the illustration of these views, yet there seems to be no 

 reason to doubt that this law, which operates so actively and beneficially now, was 

 equally efficient in earlier periods of the earth's changes. 



The earUer deposits are those of the sea in its depths, and along its shores, and 

 (as it has been said) " our examination of the structure of the existing land is no- 

 thing more than the examination of the successive deposits in the ancient ocean, 

 varied by the effects of subterranean movements." (Phillips.) 



But these views of the aqueous forces, and their action, assume a special interest 

 from the beginning of the tertiary period, on account of the marked geographical 

 relation of the marine tertiary strata to the present basins and arms of the ocean, 

 and the analogy of the tertiary sediments to the daily production of the existing 

 seas and rivers. The distinct separation of the tertiary from the cretaceous deposits, 

 the difference of the organic remains constituting distinct groups of life, and the 

 similarity or identity of the organic remains of that period, to those of the existing 

 races in the sea and on the land, together with the reasons before mentioned, have 

 led to the opinion that the tertiary commences a new condition of the globe, inti- 

 mately related to the present state. (Phillips.) 



And another reason for this opinion may be added to the above, which seems to 

 me to possess hardly inferior weight; and that is, the general conformity of the tidal 

 motions, both wave and current motions, of the tertiary period to those now existing, 

 and the adaptation of those motions, under the laws of action as here understood, to 

 produce those results which are apparent in the present form and distribution of 

 the tertiary deposits. 



