﻿598 DE. A. p. YOUNG ON THE STRITIGEAPFY AXD [XoV. I908, 



rainuta, and several others. The igneous character of the serpen- 

 tine is recognized ; but otherwise the descriptions and sections seem 

 to assume a normal and continuous succession of beds, from the 

 Triassic dolomite below to the youugest 'Kalk-thon' and Wetz- 

 schiefer above. 



In the same year Dr. F. E. Suess ^ published the results of his 

 own studies in this region. The serpentine and quartzite-schists 

 are held to be older than the calcareous schists and dolomites, and 

 it is supposed that they were brought into their present position by 

 a thrust or long fold with a push towards the north ; the beds below 

 the thrust-plane are held to be in normal sequence. 



In 1903 appeared Prof. Termier's ^ paper on the structure of the 

 Eastern Alps. The author accounts for the presence of these rocks 

 by means of one or more recumbent folds (nappes), the roots 

 (racines) of which are to be sought in the region of the Zillerthal 

 Alps. 



in 1905 appeared Prof. Erech's^ work on the structure of the 

 Central Alps of Tyrol. He adopts the explanation of the structure 

 of the Tarnthal mass already given by Dr. Suess. 



Desceiption op the Eocks of the Taenthal Mass. 



The whole of the lower ground of this district, over a wide area 

 to the west and south of the mountain, is occupied by calcareous 

 schists, the ' Brenner Schiefer.' These rocks reach up to the floor 

 of the great cirque, at a level of 2100 metres above the sea on the 

 western slope of the Tarnthal mass. Erom this point a continuous 

 section is exposed up to the summit of the ' Nederer,' marked 

 2758 m. on the ' Generalstabskarte.' 



The series commences with a massive dolomite, usually identified 

 with the ' Hauptdolomit.' This rock shows no bedding-planes ; 

 it covers the slope for the next 330 metres (1082 feet). 



Above this rock, and resting upon the dolomite at the level of 

 2480 metres, is the bedded limestone, the probable source of a 

 fossil which I found on the slopes below, apparently of Liassic age. 

 These cliffs must also include the site of the Rhsetic fossils dis- 

 covered by Prof. Rothpletz. The beds dip north-eastwards at an 

 angle of about 20°. The softer bands of the rock appear to have 

 been affected by shearing ; the fossils also present evidences of 

 distortion and faulting ; but the more massive bands cannot have 

 been very much disturbed. The thickness of these inclined beds 

 is estimated at 15 or 20 metres (50 to 65 feet). 



^ ' Das G-ebiet der Triasfalten iin Ifordosten der Brennerlinie ' Jabrb. d. k. k. 

 Geol. Reichsanst. vol. xliv, p. 589. 



^ ' Les Nappes des Alpes Orientales & la Synthese des Alpes ' Bull. Soc. Geol. 

 France, ser. 4, vol. iii (1903) p. 711. 



^ ' Ueber den Gebirgsbau der Tiroler Zentralalpen ' Wissensch. Erganzungs- 

 hefte zur Zeitschr. des T>. u. O. Alpenvereins, vol. ii, pt. i. 



