ANNIVEESAEX ADDEESS OF THE PRESIDENT. Ixiil 



question is, " To wliich do they show the greatest affinity ? " After 

 describing the seventy-one fossil species, with their separate locali- 

 ties in these two zones, he points out the complete independence 

 of the two faunas. In the Alps only one species, Flacunopsis 

 Schaflidutli, is common to the two zones, although it is admitted 

 that in other districts the separation between the two is not so 

 complete. Pecten Vcdoniensis and P. Lugdunensis of the lower 

 zone appear in the Lyonnais to belong to the Infralias. Mytilus 

 semicircularis of the upper zone is said to occur in Lombardy in 

 the Avicwla-contorta bed ; and Spondylus liasinus of the upper 

 zone is probably the same as Flicattda interstriata of the Avicula- 

 contorta zone. But even admitting these identifications to be 

 correct, there would be only 10 per cent, of the species common 

 to the two faunas, whereas at least 13 per cent, of the species of 

 the upper zone pass upwards into the Gryphaea-limestone. This 

 independence is fully admitted, he proceeds to say, by those geo- 

 logists who, like MM. Oppel, Glimbel, "Winkler, "Wright, and 

 Moore, place the Infralias (zone of Ammonites planorhis and 

 A. angulatus) in the Lias, and the Avicida-contorta zone in the 

 Trias. But others look upon these two zones as mere subdivisions 

 of the Infralias, which they consider as the lower division of the 

 Lias. M. Eenevier then objects to what he considers the undue 

 extension of the term Infralias. He proposes that this term 

 should be rejected altogether, and that the upper zone should be 

 called the Etage Hettangien, and the Avicida-contorta beds the 

 Etage E-hsetien. 



After all, he admits that the question is not of very great im- 

 portance, the chief point being that geologists should be agreed 

 as to the stratigraphical position of the beds ; and he observes, 

 with great justice and candour, that as the fauna of a formation 

 does not everywhere consist of the same species, but varies con- 

 siderably in different localities, it is not impossible that the fauna 

 of these transition- formations should in one district have a greater 

 analogy with that of the over]ying beds, whilst in another locality 

 it might have greater affinities with the fauna of the underlying 

 beds. In this case, however, the twenty-one genera hitherto found in 

 the Ehsetic beds of the Vaudois Alps have a much greater affinity 

 with the Liassic and Jurassic beds than with the Trias, inasmuch 

 as there are only two genera common to these beds and the Trias, 

 whereas thirteen genera are common to them and the overlying 

 formations ; so that, as far as the Vaudois Alps are concerned, he 

 considers the Ehsetic beds as belonging rather to the Liassic than 

 to the Triassie formation. This result is intermediate between 

 the two theories. With the one he recognizes the independence 

 of the two formations, and with the other he is disposed to con- 

 sider the Bhsetic as Liassic rather than Triassie. The main point, 

 however, is that he considers them as distinct formations inter- 

 mediate between these two great divisions. I will merely furtlier 

 observe, that the conclusions at which M. Eenevier arrives are 

 mainly the same as those of Mr. Boyd DaAvkins in his paper on 



