Miss M. M. Ogilvie — Coralinthe "Dolomites. 



53 



apparent reef-structure as at Sett Sass (Quart, Journ. Geol. Soc. 

 1893, pp. 58-77). I wish now to refer to inclined fault-planes. 

 Mojsisovics first hinted at their occurrence in the dolomites,^ e.g. 

 "on the slopes towards the Duron Valley a partial overturning, 

 or perhaps more correctly, over-thrusting of Werfen shales over 

 Muschelkalk dolomite seems to have occurred. The exposures 

 along the road leading from the Duron Valley up Col Rodella 

 scarcely permit of any other explanation. At the edge of the Bodella 

 Faidi-hlock Melaphyre dykes occur south-ivest of Col Bodella " (he. cit. 

 p. 189 ; the italics are mine). 



I drew attention to the occurrence of fault-planes with extremely 

 low hade in the Diirrenstein Mountain, and again in the Buchen- 

 stein Valley, north of Arabba ; but, as the subject was a large one, 

 and as I had not then completed my survey of the Buohenstein and 

 Sella districts,^! avoided treating it within the scope of my previous 

 paper. The planes at Durrenstein hade south, the plane I referred 

 to in Buohenstein was an overthrust fault-plane hading north. 

 Dr. W. H. Salomon published a preliminary note^ of his survey 

 ill the district of Marmolata Mountain, south of the Buohenstein 

 and Cordevole Valleys, in which he reports that two overthrust 

 fault-planes occur on the southern slopes of Marmolata hading north. 



I shall at present confine myself to one typical example of the 

 occurrence of an overthrust plane and its explanation of an apparent 



S.S.E. 



Sasso Pitschi 



Pordoi Joch. 



N.N.W. 

 Sasso Pordoi. 



Z684rrv. 



CK = Cipit limestone. 



C =Cassiaa strata. 

 "W = Weng-en strata. 



The example selected 



DD =Dachstein dolomite. 



E=Eaibl Marls. 

 SD = " Sclilern dolomite " and limestone. 

 TP= Thrust-plane. 



"Reef" in the district personally surveyed. 



is Sasso Pitschi (see accompanying section), a dolomite summit south 

 of the Sella massif. It is a reef-like mountain, standing up from the 

 midst of Wengen beds on the Pordoi Joch. As will be seen from the 

 description given by Mojsisovics (loc. cit. p. 238) the interbedding 



1 At the British Association Meetina: in Edinburgh, July 1892, Prof. Lapworth, 

 towards the close of his Presidential Address to the Geological Section, referred to 

 the country of the dolomites as one which he believed would be found to be cut by a 

 great many overthrust fault-planes. 



2 I hope soon to publish a geological map of the district between Sella Joch and 

 Wolkenstein on the West, and Cortina d'Ampezzo on the East, surveyed to scale 

 1 : 25,000 ; and to give along with it a complete statement of my results. 



3 Dr. W. H. Salomon, " Ueber den geologischen Ban und die Fossilien der 

 Marmolata," Yerh. der k.k. geol. Reichsaustalt, 7th March, 1893. 



