CXVl PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



through a very extensive range of deposits, and that the Panchina 

 deposit has continued from the age of the E. meridionalis up to the 

 human period. 



The recurrence of species apparently lost, or the re-appearance of 

 the same physical species, is strongly marked hy Signor Cocchi : he 

 says, it is deserving of remark, that the species of the yellow sands 

 are not those of the clays, but such a fact must not be used as an 

 argument for a succession of creations, since it is observed that where 

 there is an alternation of the clays and sands, there is also an alter- 

 nation of the species corresponding to each ; thus again bringing 

 before us the necessity of restricting the views so long entertained 

 of the abrupt lines of demarcation of successive faunae. 



On this subject I shall at the conclusion of my address say 'a few more 

 words, and I shall therefore close my references to Signor Cocchi' s 

 paper, which deserves an attentive perusal, as it is rich in informa- 

 tion on the general structure of Tuscany, by stating that he places 

 the eruption of trachytic rocks within the pliocene epoch, and con- 

 siders that the last great elevation of the Apennines, to which the 

 present form of the country was due, took place within that epoch, 

 and probably at the time of the trachytic eruption. 



I have received, through the kindness of M. Pictet, a copy of a mono- 

 graph, by himself and M. Alois Humbert, of the Chelouians of the 

 Swiss jMollasse, and I shall notice it here in orderlto afford another 

 striking example of the local peculiarities which so strongly mark 

 the tertiary deposits, and thereby increase the difficulty of placing 

 those of distant and widely-separated countries in co-ordination with 

 each other. In this work, after enumerating the writers who had 

 previously treated upon the Chelonians of Switzerland, M. Pictet 

 mentions the following localities at which he has himself found their 

 remains : viz. 1, in the molasse of Vengeron, near Chambeisy, 

 Canton of Geneva ; 2, in the molasse and lignites of the neighbour- 

 hood of Lausanne ; '6, in the molasse of Yverdun ; 4, of Mount Mo- 

 liere, near Estavayer ; 5, the molasse of the Cantons of Berne and 

 Argovia ; C, the freshwater marls of Chaux de Fonds ; 7, the mo- 

 lasse and lignites of Zurich and the east of Switzerland ; 8, the cele- 

 brated Q^niii^en deposits. These local deposits M. Pictet arranges 

 in five distinct stages ; the lowest being the freshwater molasse 

 of the Cantons of Yaud, Berne, and Argovia, including that of Ven- 

 geron, which rests unconformably on the red molasse, the lowest 

 member of the series. 



This formation, or series of deposits, admits of subdivision into a 

 great number of beds of considerable thickness ; for instance, the 

 grey or molasse proper 1260 feet thick, the red or lower molasse 

 995 feet, and others of very small proportions. The molasse with 

 lignites of Lausanne lies between the grey and the red molasse,: in 

 the red molasse vegetable remains only have as yet been found ; but 

 both in the molasse with lignites and in the grey molasse, associated 

 with the remains of vegetables, the bones of large terrestrial animals 

 have been found, in addition to the Chelonians, the more imme- 

 diate subject of M. Pictet's essay; and it is somewhat curious that 



