1848.] MURCHISON ON THE STRUCTURE OF THE ALPS. 165 



however, we had no other grounds than that the mass was inferior to 

 lias, and that besides salt and gypsum, it also contained a bivalve re- 

 sembling forms known to us in strata of that age. Recently, how- 

 ever, this point has been satisfactorily established in respect to the 

 Alps of the Tyrol, and I will here offer a few evidences of the age 

 of the formation which fell under my notice in the autumn of 1847, 

 when I accompanied MM. von Buch and de Yerneuil to St. Cassian 

 and the adjacent tracts, and also when we explored the same series 

 around Recoaro, north of Yicenza. 



The trias of the South Tyrol with which I am acquainted, consists 

 of a group of sandstones, marls and limestones, the latter rarely in the 

 state of dolomite, which ranges from E.N.E. to W.S.W., between the 

 transition and crystalline rocks of the central axis (Brunecken, Brixen, 

 &c.) on the north, and the great masses of alpine limestone (liassic and 

 Jurassic), which to the south, for the most part in the state of dolo- 

 mite, range from the Ampezzo Pass to Botzen. This trias is pecu- 

 liarly well exhibited in the Grodner valley to the east of the great 

 road between Botzen and Klausen. The portion of this tract which 

 lies around the little mountain village of St. Cassian*, at the limit of 

 the German and Italian Tyrol, is that which has afforded the great 

 variety of fossils first made known to naturalists by Count Miuister, 

 and since described by M. Klipstein. A great number of these 

 forms being of new and unknown species, considerable doubt hung 

 over the precise age of the deposit. This obscurity has been prin- 

 cipally cleared away by an excellent short memoir of M. Emmerich, 

 who, working out the details of a district rendered classical twenty- 

 five years ago by the researches of Leopold von Buch, has clearly 

 exposed the order of the strata, thus leaving little or no doubt, that 

 the chief and peculiar group of fossils of those Alps belongs to the 

 trias. Still the subject required confirmation, and M. von Buch being 

 as desirous as myself of re-examining the tract, I had the good fortune 

 to accompany him and M. de Verneuil thither. Ascending from the 

 Eisach Thai at Atzwang, we passed under the grand dolomitic peaks 

 of the Schlerns mountain, by Seiss and its bosses of melaphyre, toCastel 

 Ruth. The plateau which there constitutes the base of all the overlying 

 masses of limestones and marls, is a spotted red and green or tru^e 

 hunter sandstein, a very good building-stone, with strong courses of 

 subordinate white sandstone. At St. Michael we examined the col- 

 lection of fossils made by M. Clara, the venerable clergyman of that 

 hamlet, in the strata which form slopes beneath the lofty escarpments 

 of Paflatsch Berg, a promontory of the Seisser-Alp, to the south of his 

 residence. Among these fossils we at once recognised the well-known 

 Trigonellites pes-anserls of the muschelkalk (Myaphora or Trigonia) 

 with many fragments of the stems of the lily encrinite, together with 

 certain forms of Avicula and Posidoniaf, and we were therefore at 



* St. Cassian is upwards of 5000 English feet above the sea and near the head of 

 the transverse valley, whose waters flowing from south to north fall into the Rienz 

 west of Brunecken. 



t The most remarkable of the Posidoniac has been named by M. Emmerich 

 P. Clarce, after the venerable pastor, who had discovered the Triyonellites pes- 



