112 Prof. Sedgwick and Mr. Murchison on the 



that we have, consequently, no right to exclude them, at least 

 hypothetically, from the Salzburg valleys; and lastly, that the 

 tertiary deposits do sometimes ascend (e. g. at Hairing) far up 

 the transverse valleys of the neighbouring portions of the chain. 

 If all this be admitted, we must allow — that there is no great 

 d priori improbability, much less any impossibility, that the 

 Gosau beds should be of some age newer than the chalk. If 

 it be further considered — that there is a great break between 

 the calcaire grossier and the chalk, which has not yet been 

 filled up — that in the neighbourhood of Maestricht, beds have 

 been found superior to the chalk, and containing a mixture 

 of secondary and tertiary shells* — and that the portion of the 

 chain we are describing, underwent its last elevation since the 

 commencement of the tertiary period ; we must then also con- 

 clude — that the regions bordering on the eastern Alps are the 

 very places where we ought to look for the presence of an- 

 cient tertiary formations. 



If the eastern Alps have been elevated at so recent an epoch, 

 may there not have been on their flanks a continuous succes- 

 sion of deposits, between the newer secondary and the older 

 tertiary periods ? And is it not further probable, that the older 

 tertiary rocks, having been deposited in deep water, may con- 

 tain a mixture of pelagian shells not commonly found among 

 the fossils of more shallow basins? All this is undoubtedly 

 nothing but hypothesis : but it has reference to existing facts, 

 and tends to bring the perplexing phenomena of the Alps 

 under those laws by which the development of successive for- 

 mations appears to have been generally governed. 



After all, the age of the Gosau beds must be determined by 

 their relations, structure, and fossils. There is nothing in their 

 relations and structure which, in our opinion, proves them to 

 be older than the chalk : and on examining the Gosau fossils 

 on the spot, it is impossible to deny, that from their state of pre- 

 servation, the great preponderance of univalves over bivalves, 

 and the incredible abundance of shells of certain genera, sel- 

 dom found except in the newest formations, the whole group 

 has a decidedly tertiary appearance. At the same time, there 

 are a few shells (Hippurites, Gryphites, Plicatulae, &c. &c.f) 

 which forcibly reminded us of the fossils of the newer secondary 

 strata. 



Since our collection of Gosau fossils reached England, it 



* See the abstract of a paper by Dr. Fitton, Phil. Mag. and Annals of 

 Philosophy, Feb. 1830, p. 140. 



t The Hippurite of Gosau, is not of the same species with that found 

 in the secondary rock of Untersberg; and we have before remarked that 

 Hippurites are not confined to secondary formations. 



has 



