2 Miss M. M. Ogilvie— Coral in the ''Dolomites:' 



ridge, south of Groden and Enneberg, apparently the outer- 

 most at that time, formed the basis for a more or less continuous 

 barrier-like chain of reefs, behind which (i.e. to the north) deposits 

 collected of a different nature from the ordinary marine deposit of 

 the Southern Ocean. These deposits include in their uppermost 

 horizons the wonderful Cassian fauna of Enneberg, and probably 

 the faunal conditions of the Cassian-Enneberg sea of Triassic South 

 Tyrol may be justly compared with these of the Caribbean Sea at 

 the present day. At a later Triassic period, in Kaibl time, banks of 

 reef-coral were formed on raised beds of ordinary submarine deposit. 

 On the other hand there is every reason to suppose that in the par- 

 ticular periods of Trias in South Tyrol pre-eminent for the growth 

 of Coral Eeefs, the sea-floor was undergoing extensive movements of 

 subsidence, subject to oscillation in the near vicinity of volcanic 

 action. In the St. Cassian area, between the two main periods of 

 Coral gi'owth an interval of quiet subsidence intervened, marked in 

 many places by the cessation of Coral growth and the accumulation 

 of a marine deposit enclosing calcareous algge.' 



The Wengen and Cassian Coral Reefs of Groden, Enneberg, and 

 Upper Fassa have remained, with biit rare exceptions, limestone. 

 The actual thickness attained by the individual lenticular Coral Reefs 

 or the Coral Banks is in no case very great, seldom more than 

 150 feet, and usually much less. The steep slope of the outer chain 

 of reefs was mainly composed of volcanic rock with interbedded 

 reef-limestones. As negative evidence it may be mentioned that 

 the so-called "Dolomite Reefs," viz. the thick dolomite massifs of 

 Schlern, Sella, etc., have originated as marine deposits and not Coral 

 Reefs, probably calcareous in the greater part of their thickness, and 

 only in their upper horizons originally dolomitic. The reef-like 

 appearance assumed by these dolomite massifs is in small measure 

 due to the variation in the character of contemporaneous Triassic 

 deposits, but it is chiefly the result of the movements of the rocks in 

 Tertiary time. 



I have selected for the sketch-map^ a long stretch of country 

 between the Eisack Valley, with the Brenner railway on the west, 

 and the Ampezzo Valley on the east. The map displays at a glance 

 the characteristic physical features. Precipitous rocks, generally of 

 a creamy or rose-tinted crystalline dolomite, rise to great heights 

 above green swelling passes and grazing land, or sometimes descend 

 at once into deep gorge-like vallej's. The artistic sense scarcely 

 knows which to love most — the romantic region of fir-wood and 

 stream and human habitation, or the wild solitariness of the rocks 

 beyond. Villages are perched midway between mountain and 

 ravine, looking in some of the narrower valleys as if a push would 

 throw them into the gap below. The simple Ladinian folk wander 



^ Mr. George Murray made the following observation in the Antilles: — "Many- 

 coralline sea-weeds living at greater depths than the Corals grow with a stout 

 incrustation of carbonate of lime, and thus form great masses which seem to nearly 

 rival the true Coral Eeefs in bulk " (" Nature Notes," February, 1891). 



2 The Map will appear in the February Number with Part II. of this paper. 



