344 M. Ogilvie Gordon — Fauna of Tipper Cassian, South Tyrol. 



and nodular iron ore. Sometimes the sandy material occurs in 

 patches, sometimes in layers a few inches thick, sometimes in 

 layers as fine as the finest dust. The chemical decomposition of the 

 calcareous and the volcanic material and the weathering-out of the 

 finely and coarsely interlayered sands and tuffs from the rock 

 largely account for the frequent occurrence of toothed and fantastic 

 erosion forms at this horizon of the Schlern Dolomite. 



The relations of these dolomitic and sandy layers are such • as 

 are presented to us in recent descriptions of volcanic and organic 

 muds in the vicinity of oceanic islands, or more generally of ' Red 

 Ola}' ' and pelagic * Oozes.' I have always held that the deposits 

 of Raibl age represented the actual sediments in South Tyrol in 

 which a dolomitic character may be regarded as original (" Coral 

 in the Dolomites," 1894, pp. 11-13, 20-22), and that it was there 

 associated with chemical decomposition going on contemporaneously 

 with sedimentation. My specimens from this horizon are under 

 examination in Prof. Armstrong's laboratory at South Kensington. 



The chemist is confronted in the dolomites with the same 

 possibilities of chemical decomposition and interchange, both in 

 the past submarine and in the present subaerial conditions, which 

 were clearly set forth by Sir John Murray in his Presidential 

 Address to the Geographical Section, British Association, 1899, 

 from which I quote the following passages : " The inorganic con- 

 stituents of the Pelagic Deposits are for the most part derived 

 from the attrition of floating pumice, from the disintegration of 

 water-logged pumice, from showers of volcanic ashes, and from 

 the debris ejected from submarine volcanoes, together with the 

 products of their decomposition. . . . . If the whole of the 

 carbonate of lime shells be removed by dilute acid from a typical 

 sample of Globigerina Ooze, the inorganic residue left behind is 



quite similar in composition to a typical Red Clay The 



volcanic materials in a Red Clay having, because of the slow 

 accumulation, been for a long time exposed to the action of sea- 

 water, have been profoundly altered." The massive- manganese-iron 

 nodules and zeolitic crystals present in the deposit are secondary 

 products arising from the decomposition of these volcanic materials." 



The development of organic and inorganic muds, with all possible 

 variations in the alternative bedding, is the normal character of the 

 Schlern Dolomite within Enneberg and Ampezzo. And, as I pre- 

 viously pointed out, the contemporaneity of this dolomitic series, 

 in whole or in part, " with fossiliferous Baibl strata elsewhere (e.g. 

 tJie Schlern Plateau strata) would in nowise afford evidence of ike 

 Coral Beef Theory, but only of the familiar fact of Baibl heteropism." 

 (" Coral in the Dolomites," 1894, p. 13.) 



The dolomite cliff and marls in Falzarego Valley, Roces Alpe, 

 and Travenanzes are succeeded by a well-defined group of sand- 

 stones, shales, and shaly limestones, in which a typical Raibl 

 fauna occurs. The fossils enumerated at this horizon, in the above 

 table of Upper Trias, were all personally collected from a number 

 of places along this high mountain terrace above the valley. Strange 



