Rev. A. Irving — Triamc Beposifs of the A/ps. 503 



dolomite. Megalodus Triqueter (in casts) abounds in these Upper 

 Limestone strata. 



A walk of two or three days through the Grodner Thai and on to 

 Cortina offers an excellent study of a considerable portion of the 

 Alpine Trias. Leaving the deep gorge-like valley of the Eisak, 

 which presents us with splendid sections of the volcanic series, we 

 find ourselves during the first part of the ascent of the Grodner Thai 

 down among the metamorphic rocks. As we ascend the valley 

 mounting up enormous heaps of moraine debris, we come again 

 among the volcanic series. The enormous dimensions of the blocks 

 of quartz-porphyry and altered ash which make up these moraine- 

 heaps is astonishing even to one who has seen a good number of 

 moraines in other parts of the Alps. Here and there the sides of 

 the valley are seen falling back into gentle curves, suggesting the 

 incipient stage of the formation of cirques by the weathering away 

 of rocks with transverse planes of weakness. The principal moraine, 

 as it now appears, seems to explain the existence of a quondam lake, 

 which some six centuries ago is said to have filled all that part of 

 the valley in which S. Ulrich now lies. In the neighbourhood of 

 this thriving village (the ' Hauptort ' of the ' Gemeinde ') the 

 Verrucano may be very well observed. On mounting up the steep 

 ascent from St. Ulrich to St. Jakob a capital study of the Buuter 

 series is offered. These strata abound here in gypsum, and are in 

 places fossiliferous, Posidononiya Clarce being rather abundant. 

 The scenery along the line we have defined includes the magnificent 

 Sella Group, and further to the east the Trai Sassi, Tofana, the 

 Cinque Tori, Serapiss, etc. The rest may be gathered from the 

 sections described above. What has been here said of a particular 

 district affords a fair sample of the ' Dolomite Alps,' which occupy 

 an extensive region extending eastward from the Eisak Thai and 

 southward from the Puster Thai. The almost unique scenery of the 

 region seems to result from (1) the nearly horizontal lie and position 

 of the major portion of the dolomitic strata ; (2) the almost vertical 

 weathering through of the beds, partly as a consequence of (1) ; 

 (3) the splintery fracture of many of the hardest and most com- 

 pact beds ; (4) the interbedding of marly deposits with the dolomitic 

 masses. 



In North Tirol the scenery, though not generally so striking as 

 that of South Tirol, rises however to a high degree of grandeur. 

 QMiis, with the Salzburg country, is par excellence the region of 

 valley-lakes, a very considerable number of which lie among the 

 limestone strata of the Alpine Trias. The boring through these 

 strata in the Vorarlberg Tunnel now in progress from Landeck to 

 Bregenz, will doubtless throw much light on the succession of the 

 series in their more western development. An example of the enor- 

 mous extent to which these strata have in places undergone dislocation 

 is presented to us in the Achensee. This beautiful lake appears to 

 lie in a line of fault, the throw of which must be 4,000 to 5,000 feet. 

 The evidence of this, so far as I have been able to observe it, is the 

 dip of the strata at a high angle, on the west side from the lake, on 



