FOURFOLD DIVISION. O/ 



CHAPTER IX. 



Strata of the Tertiary Series, 



The Tertiary Series introduces a system of new pheno- 

 mona, presenting formations in which the remains of animal 

 and vegetable life approach gradually nearer to species of 

 our own epoch. The most striking feature of these forma- 

 tions consists in the repeated alternations of marine deposites, 

 with those of fresh water (see PI. 1, sect. 25, 26, 27, 28.) 



We are indebted to Cuvier and Brongniart, for the first 

 detailed account of the nature and relations of a very im- 

 portant portion of the tertiary strata, in their inestimable 

 history of the deposites above the chalk near Paris. For a 

 short time, these were supposed to be peculiar to that neigh- 

 bourhood; farther observation has discovered them to be 

 parts of a great series of general formations, extending 

 largely over the whole world, and affording evidences of, 

 at least, four distinct periods, in their order of succession, 

 indicated by changes in the nature of the organic remains 

 that are imbedded in them.* 



Throughout all these periods, there seems to have been 

 a continually increasing provision for the diffusion of animal 

 life, and we have certain evidence of the character and 



• In Vol. II. of his Principles of Geology, Mr. Lyell has given an in- 

 teresting map, showing the extent of the surface of Europe, which has 

 been covered by water since the commencement of the deposition of the ter- 

 tiary strata. 



M. Boue, also, has published an instructive map, representing the man- 

 ner in which central Europe was once divided into a series of beparate ba- 

 sins, each maintaining, for a long time, the condition of a fresh-water lake; 

 those which were subject to occasional irruptions of the sea, would, for a 

 while, admit of the deposition of marine remains; the subsequent exclusion 

 of the sea, and return to the condition of a fresh-water lake, would allow 

 the same region to become the receptacle of tlie exuvjB of animals inhabitimr 

 fresh-water.--Synoptische Darstellung dcr Erdrinde. Hanau,. 1827. The 



