Dr. A. P. Youug— Structure of the Tarntal Mass. 339 



Fig. 



EXPLANATION OF PLATE XIV. 



Homalostega anglica. x 20. 



Ditto, with rudimentary avicularia. x 20. 



Homalostega biconvexa. x 20. 



Ditto, with perfect avicularia. x 20. 



Homalostega vespertilio. x 20. 



Homalostega cuinformis. x 20. 



Ditto, diagrammatic longitudinal section through cell. 



[To be continued in our next Number.) 



II. — Notes on the Structure .a.nd Physiography of the Tarntal Mass. 



By Alfred P. Young, Ph.D., F.G.S., etc. 



(PLATES XV-XVIII, WITH DIAGRAM AND MAP.) 



rpHE mountain mass known as the Tarntaler Kopfe, situated about 

 1_ 20 kilometres south-east of Innsbruck, is distinctly isolated 

 from other high ground in the vicinity. The peaks rise to heights 

 approaching 2900 metres above sea-level. The geologic features 

 above the level of 2000 metres are of special interest. The adjacent 

 country is occupied by crystalline phyllites, chiefly displayed on the 

 north, and highly foliated calcareous schists developed mostly on the 

 south of the mountain. 



Sonn en spitz 



^2^63^; ^''^^^ ^^^^'^ '^PP^ 



2 8.36. • 



Keckner 



Fig. 9. Diagram illustrating the section (see infra), to be compared also with 

 PI. XV, Fig. 1. The sequence is indicated by the same numbers as on p. 340. 



A remarkably large corrie or cirque can be recognized in the 

 accompanying figure, which is a photograph of the mountain from the 

 west (PI. XV, Pig. 1). The nearer rock-mounds (' Knappenkuchel' 

 of the inhabitants) on the lip of the corrie consist of a dolomite 

 with a reddish weathered surface, the ' Eisendolomit ', which rests 

 directly on the phyllites. The section to which attention is here 

 more particularly directed commences at the back of the corrie at 

 about 2150 metres above sea-level with a massive grey dolomite in 

 which no stratification has been detected. 



The section from the floor of the corrie, called ' Grubl ', to the 

 summit of the Nederer, is as follows (from above downwards No. 1, 

 being lowest) : — 



