Yol. 55.] THE TOESION-STRUCTUEE OF THE DOLOMITES. 593 



Large weathered blocks full of coral- and encrinite-remains are 

 characteristic of the horizon, and were first described by Eichthofen 

 in the Cipit stream between Schlern and the Seisser Alp. 



At Pitzculatsch there follows above this horizon a certain thickness 

 of interbedded limestones and marls dipping about 30° towards the 

 mountain. I found in these a typical ' Stuores ' Cassian fauna, 

 and followed the outcrop towards the Groden Pass. IS'ot only are 

 the fossiliferous marls present, but also the higher horizons of more 

 thickly- bedded brownish-yellow limestone, full of Cidaris-syymes and 

 other small fossils. The same zone of Cassian limestone is present 

 on the ridge of Pralongia above the Stuores meadows. 



Here, at Pitzculatsch, the yellow limestones are followed by thickly- 

 bedded calcareous horizons with numerous encrinite-remains and 

 blocks of coral-growth, and then succeeds the ' dolomite '-cliff of 

 Griiner Fleck. But, so far as I could examine it, this last rock gave 

 a distinctly acid reaction. 



This section therefore proves a conformable succession of the rock 

 called Schlern Dolomite (although largely calcareous in certain 

 places) upon marls and limestone containing a typical ' Stuores ' or 

 Middle Cassian fauna. No individual zone is wanting which has 

 been demonstrated and fixed palaeontologically by the writer in the 

 survey of the neighbouring typical area of Pralongia and Stuores. 

 Hence there is no reason whatever for mapping the dolomitic 

 limestone here as a ' reef-built facies ' corresponding in age to a 

 ' bedded facies ' of earthy deposits. It succeeds the Wengen-Cassian 

 Series conformably, and is therefore geologically younger than these 

 strata. 



Peripheral overthrust of Sella at the Griiner 

 P'leck. — The precipitous cliffs of the Meisules group in Sella sur- 

 mount the Pitzculatsch hill. Griiner Fleck is the name given ta 

 a grassy ledge midway up the rocks at the north-western corner. 

 Even from below it can be observed that the ' Schlern-Dolomite ' 

 rocks below the Griiner Fleck dip steeply inward with the general 

 dip of the Pitzculatsch succession, whereas the ' Schlern-Dolomite ' 

 rocks of Meisules are almost horizontal, and in their continuation 

 towards the Groden Pass dip outward from the mountain. 



This difference becomes still more evident when an ascent is 

 made to the Griiuer Fleck. Cassian marls and calcareous rocks are 

 present on the ledge, and share the strike-and-dip relations of the 

 Meisules terrace. Both the Cassian marls of the Griiner Fleck and 

 the overlying dolomite meet the lower dolomite along a disturbed 

 shear-plane ; an overthrust of certain horizons of the Cassian strata 

 and the overlying Schlern Dolomite has taken place above the same 

 horizons of rock in the Pitzculatsch conformable succession, upon a 

 plane inclined south-eastward at an angle of about 50°. Con- 

 firmatory evidence of the thrust-plane is afforded in the cliff's facing 

 the Groden Pass. 



Immediately east of the Griiner Fleck no Cassian strata are 

 apparent in the overthrust-group. Farther round, however, Cassian 

 strata come increasingly into evidence, while below the shear-plane 

 a. J. O. S. No. 219. 2 a 



