342 Dr Boue on the Formation ofTtrttary Rocks. 



difficulty, for M. Brongniart has united under the same head 

 the fossils of both these periods. If we take into account the 

 species which are not accurately classified, and which are ar- 

 ranged under the head terrain thalassique in general, (p. 380), 

 and then set aside the species from Plaisantin not classified in 

 the upper tertiary soil, and also the species from Bordeaux, 

 Dax, the Roussillon, Turin, Anjou, Brittany, and Mayence, 

 arranged erroneously under the tritonian group; and lastly, 

 those of the green-sand of Trauenstein and Diablerets, reck- 

 oned, in our opinion, erroneously amongst tertiary fossils, we 

 can construct fossil tables which, taken together, will help us in 

 the determination of the age of a tertiary deposit, at least if it 

 contains many fossils, and if we have collected them there our- 

 selves. On the other hand, it is to be regretted that M. Brong- 

 niart has omitted in his lists of fossils some very important ones, 

 viz. the crania abnormes in the Bordeaux upper tertiary, the 

 vaginella in the subappenine clay, &c. We would also wish to 

 know the reasons for distinguishing the Bolca deposit and that 

 of Salado from the nummulite tertiary limestone, with shelly 

 tufaceous volcanic rocks. If this last belongs to the tritonien 

 or inferior group, the first rocks are also of this class, for the 

 slates with fishes and plants are only an accident in that num- 

 mulite limestone, as the lignite clay in the marine hmestone at 

 Paris. A moment of hesitation must have given rise to that 

 singularity, to see the fishes of Bolca in the proteique group 

 (382), and the fucoides, and all the plants excepting the Tenop- 

 teris Bertrandi, which is associated with the last, in his tritonian 

 class (p. 393). In short, M. Brongniart will readily acknow- 

 ledge, that the imperfections of his still useful tables of fossils, 

 would conduct to strange results, if we were to take them a la 

 lettre, as the sole basis for the determination of tertiary deposits. 

 I regret I cannot agree with M. Brongniart in the characters he 

 gives to his proteique system, viz. that it contains few madre- 

 pores and no nummulites (p. 153), because the upper tertiary 

 limestone of Austria, Hungary, and Transylvania, contains 

 thick beds entirely composed of a variety of nummulites, while 

 the sands abound in coralline bodies, as is the case at Eisenstadt 

 in Hungary. In the subappenine clay marl, madrepores are 

 gather unfrequent, excepting the genus turbinolia, &c., but they 



