﻿Vol. 6 I.] DOLOMITES OF SOUTHERN TYEOL. 125 



areas where the rocks have not been dolomitized. My collection 

 was made, primarily to illustrate the chemical and mineralogical 

 characters of the rocks from various horizons ; so that most of 

 the fossils recognized were those met with in the examination of thin 

 sections from the limestones and dolomites. 



The Schlern Dolomite. 



Very few of the hand-specimens of Schlern Dolomite contain 

 recognizable organisms. Corals are occasionally found in the mass 

 of the rock from various horizons. They are almost always found 

 as casts in dolomite, and only in a few places occur in abundance. 

 In thin sections the calcareous algse are the commonest fossils, 

 especially various species of Gyroporetta (Dlplopora). Echinoderm- 

 spines and lamellibranch-shells are not uncommon here and there ; 

 while foraminifera are occasionally found. 



Sections of 38 specimens of Schlern Dolomite were examined 

 under the microscope, and only one coral was recognized with 

 certainty ; while eleven other sections showed meandrine areas of 

 cloudy dolomite, which might represent corals, but the loss of 

 structure during dolomitization had been so great that not much 

 confidence could be placed in their identification. Calcareous algse 

 were recognized in three sections, and organisms doubtfully referable 

 to them occurred in five other slides. Sections of shells (probably 

 lamellibranchs) and echinoderm-spines were each recognized in 

 single slides. No less than seventeen sections of the dolomites, 

 representing about 45 per cent, of the sections examined, failed to 

 yield any traces of organic structure. 



Deposits below the Schlern Dolomite. 

 St. Cassian Limestone. 



Four sections were examined, and fossils were found to be more 

 abundant and better preserved than in the dolomitized strata. In 

 one section, a coral was seen, the structure of which was perfectly 

 preserved in its original aragonite. Two sections contained 

 numerous examples of more than one genus of calcareous algae. 

 Three of the sections showed fragments of shells, probably lamelli- 

 branchs ; while one section contained the chambers of one of the 

 foraminifera and also a tubular organism, probably a polyzoon. 



Wengen Beds. 



But one section was examined, and the only recognizable 

 organisms were lamellibranchs. 



Buchenstein Limestone. 



Two sections were cut : algse occurred in one, lamellibranchs in 

 the other, and foraminifera in both. 



