170 Dr Boue on the Formation of Tertiary Rocks, 



therien dans le calcaire moeUon des terrains proteiques de Mont^ 

 pellier, ti' est pas une ojiomalie aux generalites reconnues dans 

 lesjm'ynations, et elle ne detruit aucune idee re^u ni oter aucune 

 vakur aux characteres zoologiqueSy (p. 203). — Without asking 

 whether that assertion is in accordance with another, where it is 

 said, that La sticcession des generations est le moyen le plus sur 

 et peut-etre le seul pour determines les epoques geognostiques 

 (p. 159), we shall take the statement as offered to us, and as 

 a sufficient proof that the bodies of animals, or bones, have been 

 carried down by rivers, without interruption, during the whole 

 tertiary period, and that the same species lived during that time 

 on the surface of the earth. It seems, then, we must abandon 

 that hypothesis of a gypsiferous lake, surrounded by beaches 

 inhabited by animals, which did not exist before the paleothe- 

 rian period. The theory was ingenious, but facts overturned 

 it. 



Although we are not disposed to admit a favourite hypothesis 

 of Brongniart, we are ready to range ourselves under his ban- 

 ners, when he finds it more rational to bring the gypsum and 

 strontianite from the bowels of the earth (p. 196), than from a 

 distance through the agency of water, as is the opinion of Pre- 

 vost. During some of the great eruptions that took place in 

 Auvergne, or nearly about that time, we can easily conceive, that 

 aqueous and acidulous emanations may have found their way 

 to the surface by great rents, indicated partly by the beds of the 

 Loire and Allier, also by the Channel. These phenomena were 

 only a repetition of what formerly took place after every ex- 

 tensive eruptions ; and volcanoes still act in the same way. It 

 was such an irregular emanation of acids which produced the ir- 

 regular interlacing of the paleotherian rocks, a fact on which 

 Brongniart lays much stress (p. 156). 



We may add, that our explanation of the marine formation of 

 the gypsum, resolves all the difficulties which M. Brongniart 

 finds, when speculating on the return of the sea into a fresh 

 water basin, and explains also the deposit of the superior ter- 

 tiary sandstone near Paris, a deposit which did require a long 

 time, as is shewn by its containing balanites, &c. This basin 

 must have been a salt-water lake, until the period of the begin- 

 ning of the upper fresh water limestone, the only one which has 



