244 Dr. A. P. Young—Gilaciation of Navis Valley. 
decided at present. The presence of Annularia radiata, Brongn., and 
to a less extent that of Meuropteris rarinervis, Bunb., would seem to 
turn the balance in favour of the Upper Transition Series were it not 
for the abundance of Pecopterids and the possible occurrence of 
Pecopteris arborescens (Schloth.). Perhaps we may provisionally 
conclude that these beds belong, either to the highest portion of the 
Upper Transition Series, or the lower portion of the Upper Coal- 
measures. 
II.—On tHe Guacration oF tHE Navis Vattey 1n Norra Trrot. 
By Aurrep P. Youne, Ph.D., F.G.S., F.L.S., ete. 
(PLATES XIX AND XX.) 
N a previous paper! it was shown that one prominent topographical 
feature of the Tarntal district, the great cirque called the 
‘Griibl’, could be explained as the effect of erosion by a short ice- 
tongue which formed when the snow-line persisted for a time at about 
2400 metres above sea-level. The basin-shaped hollow of the Upper 
Tarntal was held to be due to another stand of the snow-limit at 
2650 metres. It remains to be seen whether these conclusions are 
supported by evidence of a similar nature collected over a wider area. 
EVIDENCE FOR SNOW-LINES IN OTHER PARTS. 
The drainage basin of the Navis Valley is bounded on the south by 
a well-marked ridge in no part lower than 2250 metres, with several 
summits over 2400 metres; the highest, the Schafseiten Spitze, 
reaches 2604 metres. On the north slope of this ridge is a row of 
corries sufficiently conspicuous to be visible from the north slopes 
of the valley as shown in the photograph, Fig. 1, Pl. XIX. Two of 
these corries under the ridge between Bendelstein and Schafseiten 
Spitze certainly held at one time small lakes; the moraine dams at 
the outer lips are still well preserved at a level of about 2150 metres. 
The corries are evidently the beds of short ice-tongues which formed 
when the snow-line stood for a time at about 2250 or 2300 metres. 
On the northern slopes of the Navis Valley the corries are not so 
well developed. On the east slope of the Mieselkopf? is a well- 
marked amphitheatre, the floor of which is somewhat ill-defined. 
Important accumulations of moraine material are found on these slopes 
mostly at levels below 2300 and above 2150 metres; these evidently 
belong to a high snow-line, the level of which was between 2350 
and 2400 metres. 
Under the ridge which bears the Schober Spitz, 2450 metres, is 
a small but pronounced lake-basin at a level of 2300 metres, indicating 
a snow-line at 2350 metres nearly. 
Summing up the evidence from different parts of the drainage 
1 Grou. Mae., Dec. V, Vol. VI, No. VIII (August, 1909), p. 339. 
2 See accompanying map reproduced from the Grozt. Mac., August, 1909, p. 341. 
