54 Miss 31. M. Ogikie— Coral in the "Dolomites" 



of Cipit Limestones with tufaceous rocks is peculiarly characteristic. 

 The dolomite rock contains, especially at its base, remains of Corals 

 and Crinoids. Ammonites also have been found in the dolomite. I 

 find it impossible to consider the succession on Pordoi Joch undis- 

 turbed. On the south side, the Wengen lavas dip N.N.W. (20°-30°) 

 and the conformable series of Cipit Limestones (Wengen and Lower 

 Cassian age) and Schlern dolomite beds dip in the same direction at 

 a rapidly increasing angle. The rocks on the north or Sella side 

 are, on the contrary, remarkably horizontal, but where the terrain 

 descends from Sella Mountain to Pordoi Joch, the strata dip slightly 

 southward and south-eastward, i.e. outward from Sella (a dip which 

 the strata exposed on the lower half of Sella massif continue to 

 have all round its eastern side). On Pordoi Joch, therefore, we are 

 presented with a repetition of the Cipit Limestone and the dolomite 

 strata, owing to the passage of an overthrust plane of low hade, 

 above the Sasso Pitschi rock. The thrust-plane hades northward 

 and cuts away the dolomite rock of Sasso Pitschi, both in its 

 eastward and westward extension below the Cassian beds of the 

 Sella block. This fault affords to my mind a simple explanation of 

 all the appearances associated with "Coral Keef" : — 



1. That Sasso Pitschi appears to "rise out of Wengen beds " 



2. That the dolomite rock of Sasso Pitschi has a steep cliff edge to the south, and 

 a gentle slope to the north. 



3. That it thins out on Pordoi Joch, except on the western side, where it appears 

 to pass conformably under the dolomite rock of Sella massif. 



4. The " overcast bedding with northerly dip " said to be observed on the northern 

 slope of Sasso Pitschi. 



This last-mentioned appearance is clearly shown at Sasso Pitschi, 

 and is by no means the only case in v/hich I believe it to be the 

 result of fault movement. The thrust-plane observed at Sasso 

 Pitschi may be followed with N.N.E. outcrop close under the cliffs 

 of Sella to Pian de Sass, where it also explains the seeming anomalies 

 of the succession. If we now proceed to mend this broken section 

 according to the natural succession of the district, we have a fair 

 representation of the particular volcanic zone from east to west, 

 already referred to (see Diagrams I.-IL). Here, where we are on 

 the borderland of the actual passage of Wengen and Cassian strata 

 into their deeper sea equivalents, the main thickness of these beds 

 is composed of volcanic lavas and tufaceous deposits. The Cipit 

 Limestones and the Sasso Pitschi "dolomite" may of course be 

 regarded as the direct continuation northwards of the upper part 

 of the Marmolata deposit of limestone and dolomite, continued 

 further north over Sella, Gardenazza, etc. This is an example 

 perfectly analogous, therefore, with the case of the heteropism at 

 Schlern Mountain, on its southern and northern sides, and the 

 Seisser Alpe. There is scarcely any thickness of the Cassian horizcua 

 present below the Schlern dolomite of Sasso Pitschi; the Middle 

 Cassian or " Stuores " zone partly developed as " Cipit Limestones " 

 on the Sella slopes, passes to the east and north-east into the thin- 

 bedded fossiliferous max'ls of Enneberg, and reaches a later paleeon- 

 tological development on these meadows than below Sella and 

 Sasso Pitschi. 



