Miss M. M. Ogikie— Coral in the "Dolomites" 55 



I have dwelt at some length on this example, because it shows 

 again the tektonic nature of some of the difficulties hitherto 

 professedly explained by the "Coral Eeef theory." We must in 

 every case clearly decipher the twofold nature of the difficulties in 

 South Tyrol, for, as we have seen both at Sett Sass and at Sasso 

 Pitschi, the battle is only half fought with a knowledge of the 

 Triassic period. In the latter case, Sasso Pitschi, the heteropism 

 of the Wengen and Cassian strata, together with the conformable suc- 

 cession of "Schlern dolomite," are the stratigraphical truths observed 

 at Pordoi Joch. The tektonic fact is the overthrusting from the 

 north of the system or " block " of strata belonging to the Sella 

 massif along a plane formed in this southern part by the cut and 

 tilted ends of the strata belonging to the fault-block of Sasso Pitschi 

 and Cima Rossi. It is not necessary for the purpose of the present 

 article to follow farther the course of this thrust-plane, or to describe 

 in detail others which exist in the districts of Enneberg and 

 Ampezzo, Buchenstein and Upper Groden. For the Pordoi over- 

 thrust is not an isolated occurrence, but one of several inclined 

 planes of fault which pass through strata of all ages in this part 

 of the "Dolomite Alps." Above Plan de Sass, on Sella Mountain, 

 an overthrust fault passes through Dachstein dolomite, and just 

 north of the Boe Spitz (the highest ridge of Sella) a fault plane 

 with reversed hade has raised Dachstein Dolomite against Jurassic 

 strata. The direction of these faults is S.S.W.— N.N.E., and they 

 afford the most perfect analogy with the main faulting which has 

 taken place in districts west and south-west. Suess says, in sum- 

 ming up the observations of faults in the Southern Alps (east of 

 the Judicarian fault) : "Long flexures have occurred passing locally 

 into faults, which, running parallel to the Judicarian line, have 

 let down the strata on the eastern side, and have caused over- 

 thrusting to the east, or more correctly from a W.N.W. direction 

 towards E.S.E. These extend from the Judicarian line as far as 

 the left side of the Etsch below Peri. Further, similar flexures 

 have occurred which run more or less parallel with the Asta faults, 

 lie south of these, and have let down the strata on the south, 

 and sometimes overthrust them to the south. Some of the Judi- 

 carian faults swing round in sharp curves, in the proximity 

 of the Etsch Valley, into the direction of the Asta faults" ("Das 

 Antlitz der Erde," Bd. I. pp. 334-335). It is just such a swing- 

 round that the inclined fault-plane of Pordoi and Sella shows, and 

 I may state generally that the faults of Sella may be grouped with 

 the Judicarian system, whereas those of Groden Joch, of Buchenstein 

 Valley, and, in short, the faults in this area which pass through 

 anticlines of the deeper lying Triassic strata, belong to the Asta 

 series. No hard and fast distinction can be drawn between these 

 systems; they pass into one another and form one complicated 

 system of movements, which may be proved even in the small 

 district of Enneberg to have affected the positions of both Triassic 

 and Mesozoic rocks. 



By reason of these faults, the dolomitic rock has sometimes been 



