360 Professor Sedgwick and Mr. Murchison on the 



carinaia, Trigonia aUeformis {\£ir.), and Pectcn qv inqucco statu s ; and the 

 tertiary fossils Fusits intortus, Auvicida simulata, Pectuncnlus Plumstediensis , 

 P. hreviroslris, Nucula amijgdaloides, and Cijclas cuneiformis, will appear in 

 the list at the end of this paper. We may further remark, that the above 

 tertiary species are associated with myriads of shells of the genera Mitra, 

 Voluta, Terebra, Volvaria, Cerithium, Pleurotoma, Fasciolaria, and Fusus, 

 which have hitherto been considered characteristic of beds above the chalk. 



M. Goldfuss's work* furnishes an additional confirmation of our views 

 respecting- the age of the Gosau deposits. They contain many beautiful and 

 well-preserved corals, several of which he identifies with species which occur 

 in tertiary formations ; such are, TurhinoUa duodcchncostata , T. cuneata, 

 Lithodcndron grannlosnm, and Fungia polijmorplia ; to which we may add 

 Diploclenuim cordaliun, whicii occurs both at Gosau and Maestricht. 



2. We are fully aware of the extreme difiiculty of identifying fossil species, 

 especially when derived from localities distant from each other. Very expe- 

 rienced naturalists have differed in the identification of certain species derived 

 from Gosau. For example, a Gryphiea has by some been identified with the 

 G. columba ; but M. Deshayes contends that it is a new species. From the 

 time we saw this fossil in the cabinet of M. De Lill, before we first visited 

 Gosau, we have entertained the same opinion. It has been contended, that 

 in the absence of specific characters we have no right to decide on the ter- 

 tiary age of any part of the Gosau series. We reply, that, even granting the 

 statement, the argument is worthless. For if any one chooses to affirm that 

 none of the Gosau beds are tertiary (or newer than the chalk), because we 

 know not the species of the imbedded fossils ; we have the same right to affirm, 

 from the absence of known secondary species, that none of the beds are se- 

 condary. In cases of this kind we can only foim a probable opinion from the 

 aggregate character of the fossils. And that this aggregate character is in 

 favour of our conclusion, we affirm, not on our own experience only, but on 

 the authority of every fossil conchologist whom we have consulted f. 



3. It perhaps deserves remark — that in the upper shelly group of the general 

 section (No. .'3.), univalves greatly predominate over bivalves — and that almost 



* Pedefacten von Dr. Goldfuss. 



t Because M, Deshayes has not adopted our specific enumeration of a few of the Gosau shells, 

 his authority has been very erroneously quoted as opposed to our views on the classification of 

 the whole deposit. On a question of this kind his authority is of great importance ; and from 

 the first he has contended that the Gosau shells, considered as a suite, are such as would cha- 

 racterize an old series of strata superior to the chalk. In short his opinion, founded solely on the 

 organic remains, is in perfect accordance with that which we formed, both from the organic 

 remains and the relations of the component strata. 



