THE 



GEOLOGICAL MAGAZINE 



NEW SERIES. DECADE IV. VOL. L 



No. II.— FEBRTJAEY, 1894. 



OE-IOII^rj^Xj -A.I^TIGXJES. 



I. — Coral in the " Dolomites " or South Tyrol. 



By Miss Maria M. Ogiltie, D.Sc. (Lond.). 



(Part II.) 



(PLATES II. & III.) 



[Concluded from the January Number, p. 10.) 



III. — Transitional Dolomitic Era — Extremes of Rock-Facies in 

 Raibl Times. 



The Eaibl period was the natural sequel of the variable and 

 unequal movements which prevailed over Alpine areas in Permian 

 and pre-Eaibl Triassic time. Many basins formerly open were then 

 enclosed ; rauchwackes and beds of dolomite and gypsum were 

 interbedded with fossiliferous deposits. Whereas, in some places, 

 the dolomitic nature of the deposit is confined to special horizons, 

 in the South Tyrol " Dolomites " it may almost be said to reign 

 throughout. This makes it all but impossible to say when Schlern 

 dolomite ends and Raibl beds begin. In the present incomplete 

 state of our knowledge with regard to the heteropism of the Eaibl 

 series throughout the whole Alps, I have judged it best to begin the 

 Eaibl horizon at any particular place with the first appearance of 

 a distinctly Eaibl fauna, even although that fauna may not have 

 been proved to correspond to the acknowledged lowest fauna of 

 Eaibl age in distant parts of the Alps. 



To return for a moment to the succession of Schlern dolomite 

 upon the Cassian beds of Enneberg, I found that, whei'e Schlern 

 dolomite rests on Cipit limestones, it has at its base a conglomeratic 

 appearance, as if Cipit blocks had been imbedded in a beautifully 

 fine white or reddish dolomitic mud, instead of the dingy brown 

 and black tufaceous sediments. This is the case in several places, 

 e.g. upon Pordoi and Sella Jochs, where there is no evidence of 

 unconformity. Again, where the dolomite succeeds the thin-bedded 

 marls and limestones of Cassian age, it does so conformablj'^ ; but 

 one and the same bed is at some parts calcareous and fossiliferous, 

 at other parts dolomitic and unfossiliferous. Seeing that this holds 

 good at various horizons in Lower as well as Middle Trias over the 

 whole area of South Tyrol, we need find nothing remarkable in it 

 from the point of view of the stratigraphical succession. Indeed, 

 I have only mentioned these observations as an indication of the 



DECADE IV.— VOL. I. — NO. II. 4 



