138 Reviews — Meyer's Catalogue of Tertiary Fossils. 



It is the method proposed by M. Hoernes, which places the 

 boundary line between the Eocene and the older Miocene, or be- 

 tween the Tongrien and Aquitanien stages. Let the Prussian 

 geologists say what they may, it is precisely then — at the close of 

 the Tongrien period — that in Europe the most important changes 

 took place, either with respect to the displacement of seas, or the 

 change of fauna. At that time, in the north of Europe, the sea 

 retired from the whole of the English, French, and Belgic portions 

 of the Tertiary basin, and there was a contraction of one-third of the 

 North German basin. In central Europe there was a general and 

 important elevation, or at least a first marking of the boundaries, 

 of the whole Alpine chain ; evidenced by the presence of Tongrien 

 depositions on the mountains of Faudon and St. Bonnet, of the 

 Dent-du-Midi, the Diablerets, the Titlis, &c., and by the position of 

 the earliest marine deposits, of the Aquitanien period, at the base of 

 the great Alpine wall. In the S.W. of France there was a con- 

 traction and emptying of that basin, as shown by depositions either 

 wholly fresh-water or brackish. Palseontologically considered, there 

 was nearly a complete disappearance, in the Aquitanien stage, of all 

 the Eocene species, that is of those which still in considerable 

 numbers connect the Tongrien with the subjacent stages ; there was 

 a complete extinction of Nummulites, which are still accumulated in 

 great numbers in the upper beds of the Alpine and southern zones 

 of the Tongrien stage ; — (St. Jacques near Eennes, Gaas, le Tuc-du- 

 Saumon near Dax, Faudon, Argentines in the French Alps, the 

 Dent-du-Midi, the Diablerets, Acqui, Cassinelle, Pietra-Bissara, etc., 

 in the Piedmontese Apennines ; Verona, Castel-Gomberto ;) — lastly 

 the first appearance of the great Pachyderms, and swarms of still- 

 living species of MoUusca." 



It is true that M. Meyer suggests certain Palseontological conside- 

 rations which may detract from the value of this proposed line of 

 demai'cation, such as an admixture of fossil in certain localities, just 

 as was supposed to be the case at the Bolderberg ; of such difficulties 

 as these the physical geologist sees an obvious explanation. The 

 Nummulitic group must be wholly separated from the Kainozoic, 

 and be made to constitute the uppermost member of the Mesozoic 

 series of Periods. 



The changes which M. Meyer now proposes are these : — ^I. For 

 " Mayencien " he substitutes the designation " Langhien," from a 

 chain of hills between Acqui and the upper course of the Tenaro ; 

 the change is made in deference to the dislike of the Germans to the 

 word Mayencien, — a very insufficient reason. II. Mr. Toumouer's 

 recent discovery, on the boundary of the Department of the Gers 

 and the Landes, of beds identical with the Faluns of Touraine, 

 proves that these last are not merely a facies of the Saucats beds, 

 but belong to a higher level, strati graphically distinct ; as also by 

 a fauna less rich in tropical species, richer in Mediterranean forms. 

 This level being intimately connected, in the S.W. and central 

 France as in the Swiss-German Jura, with that which follows 

 (the beds of Serravalle), it becomes necessary to unite it to the 



