574 MISS M. M. OGILVIE [mRS. GOKDOn] ON THE [Aug. 1 899, 



easterly downthrow, and crosses between Cherz Hill and Pralongia 

 into the Buchenstein Valley. 



The diagonal fault of Pescosta-Corvara is parallel with another 

 higher up the eastern slopes of the Groden Pass, which crosses from 

 the Tschampatsch dolomite- cliffs and through the Ruon fault- 

 wedge to Crap de Sella, Its downthrow is also easterly, and the 

 double throw of the Pescosta and the Ruon diagonal faults 

 explains why Sass Songe is visibly more deeply depressed than the 

 Tschampatsch, and much more than the Spitz Kofi group which 

 occupies the head of the Pass. 



The throw of the faults is increasing even at the present time. 

 The weight of the Sass Songe dolomite-cliffs is continuously pressing 

 forward and downward on the more yielding rocks of the anticline, 

 separated from Sass Songe by longitudinal dislocation. Slipped rock 

 from above fills in the transverse rupture between the Pescosta fault- 

 dyke and the valley-segment of the anticline, just as Wengen rocks 

 have filled the analogous transverse rupture next the fault-dyke at 

 the higher (Euon) slopes of the Pass (see p. 571). 



Relations of the strata described to those of the 

 massives north and south of the Groden Pass. — 

 (a) Although the downthrow of the dolomite in the cliffs north 

 of the Groden Pass is greatest at Sass Songe, the whole range 

 of dolomite in the cliffs which form the face of the Gardenazza 

 Massive is thrown down, relatively to the crumpled exposures of 

 Wengen strata that accompany the northern limiting-fault of the 

 Groden Pass anticline. A normal fault (see figs. 1 & 4, pp. 568 & 

 572) sweeps in a curving direction over the Pass always near the 

 base of the northern cliffs, and cuts off Wengen strata against 

 different horizons of Cassian strata and Schlern Dolomite. It may 

 be followed westward across the Langenthal towards the Ruine- 

 Wolken stein cliffs. 



(l3) The relation of the Groden Pass Anticline to the dolomite- 

 cliffs of the Sella Massive on the south of the Pass is so far similar. 

 Faults have passed through the steep southern wing of the anticline, 

 letting down the Sella region relatively to the Groden Pass areas. 

 But an overthrust has taken place northward from the Sella region 

 on a reversed fault- plane, inclined away from the Pass and into the 

 heart of the Sella Massive. The Sella overthrust is exposed in 

 the Cassian or Schlern Dolomite horizons ; while the Pass overthrust 

 to the south-south-east is exposed chiefly in the Muschelkalk and 

 Wengen horizons, and is accompanied by ramifying threads of 

 intrusive dyke- and sill-rocks (figs. 4-6, p. 572). 

 . The Sella overthrust will be dealt with later (p. 593), but almost 

 any photographic panorama of the overthrust as shown on the eastern 

 side of the Groden Pass will serve to exhibit the shear-zone, where 

 fragments of Cassian strata dipping outward are pushed above an 

 irregular thickness of Schlern Dolomite dipping steeply inward. 

 The reading given to these appearances in Mojsisovics's ' Dolomit- 

 Riffe ' was that of coral-built cliffs of calcareo-dolomitic rock 



