Structure of the Eastern Alps. 359 



think, be safely applied to the overlying- deposits of Gosau ; and we might 

 conclude, without more evidence, — that a portion, at least, of these deposits is 

 newer than the chalk, and belongs to a transition group in a long unbroken 

 series of formations in the Alps, which we have to interpolate between the 

 calcaire grassier and the chalk. 



If the preceding- conclusion be admitted, the sandstone groups at the top of 

 the Horn and Ressenberg- must be classed with the tertiary, micaceous sand- 

 stone (or molasse), which alternates with conglomerate, and forms so large a 

 portion of the tertiary system on the skirts of the Bavarian Alps. 



In order to leave none of the evidence for the system we have adopted un- 

 explained, we proceed to a more particular description of the fossils in the 

 preceding- groups (Nos. 2. & 3.). As their specific determination is the work 

 only of experienced conchologists, we have gladly availed ourselves of the 

 kind assistance of Mr. J. Sowerby, and have added two plates of character- 

 istic fossils, which are figured and described by that g-entleman*. 



Fossils of the Overlying Deposits of Gosau. 



1. The first time we saw the Gosau sections we felt a strong- conviction, 

 that at least a portion of the component groups were superior to the chalk, 

 and probably of the same age as some of the oldest tertiary deposits (namely 

 those at Bassano, Asolo, the Vicentine, &c.) on the southern flank of the Alps. 

 Our first impressions were greatly strengthened by the opinion of an accom- 

 plished naturalist, to whose examination we submitted some of the fossils we 

 had derived from the groups in question. Out of more than eighty species 

 M. Deshayes did not detect a single known secondary or tertiary fossil, but 

 he considered the whole suite as decidedly characteristic of an old deposit 

 superior to the chalk. Mr. J. Sowerby, to whom we submitted a still larger 

 collection, especially of the fossils derived from the inferior shelly g-roup 

 (No. 2.), coincided generally with this opinion, but thought that we might 

 identify some of the fossils both with known secondary and tertiary species ; 

 and he further pointed out the perfect identity of aTurbinolia and a Fungia of 

 Gosau, with species derived from the tertiary beds of Bassano. 



Since the return of one of the authors from his second visit to the Eastern 

 Alps, a much larger and more perfect collection has been examined by Mr. J. 

 Sowerby, and his re-considered opinions are recorded in the following- list. 

 It will be seen that he still identifies a few of the Gosau fossils with known 

 secondary and tertiary species. For example, the secondary fossils Cucullcea 



* Plates XXXVII. & XXXVIII. 



