VON HAUER — EASTERN ALPS. 27 



over a surface of 98,000,000 square feet. It terminates, at the 

 altitude of 7000 feet, at the Legerwand, where the valley sinks with 

 a nearly perpendicular slope of 300 feet. 



Since its last slight movement (in 1846), the glacier continued to 

 retire. In the spring of 185G it again became upheaved, swollen, 

 and traversed by several fissures ; until, in the middle of June, its 

 heaped-up fragments began rushing down the Legerwand, and con- 

 tinued to fall so quickly that after a few weeks a regenerated glacier, of 

 more than 600 feet in length, with ** ribboned " structure and several 

 small fissures, was formed at the foot of the precipice. After the 

 glacier began to fall over the Legerwand, it advanced more than 

 6 feet daily, and this progress materially increased after the great 

 cold of November 1856. 



A former outbreak of the same glacier took place in 1817 and 1818, 

 when it advanced 4200 feet (Austrian) within sixteen months, and 

 thrust a mass of ice of more than 1,000,000,000 cubic feet down the 

 Legerwand. 



Major de Sonklar is of opinion that such energetic movements of a 

 glacier are not to be exclusively ascribed to general meteorological 

 causes ; but that local circumstances, although still very imperfectly 

 known, must have influence on these phenomena. This observer 

 points out, that the existence of more than seventy glaciers on lime- 

 stone-mountains is opposed to the assertion made by MM. Schla- 

 gintweit, that calcareous rocks are unfavourable to the formation of 

 glaciers. [Count M.] 



On the Geology of the Eastern Alps. By Fr. von Hauer. 



[Proceed. Imp. Acad. Sciences, Vienna, January 1857.] 



In exhibiting and explaining his section* of the Eastern Alps, from 

 Passau on the Danube to Duino on the Adriatic, Chev. Fr. von Hauer 

 noticed that among the most important facts elucidated by this 

 section are, — 1st, that the triassic and liassic deposits are nearly 

 identical on the north and south slopes of the Eastern Alps ; 2ndly, 

 that the strata of more ancient date, on the two sides of these Alps, 

 differ considerably from each other; and may be regarded as having 

 been formed at different epochs, owing to violent movements in this 

 region, coincident with the palaeozoic period ; 3rdly, that the more re- 

 cent deposits of the north slope are not in accordance with those on 

 the southern slope, and must have been formed under the influence 

 of very different conditions ; 4thly, that the last upheaval during the 

 Tertiary epoch took place at a very different time on the two sides 

 of the Eastern Alps. [Count M.] 



* The scale of the original survey (prepared for the Imperial Geological In- 

 stitute) is ^^.^^ nat. size ; it is to be published on the same scale as that of the 

 Staff Corps special maps (j^^ nat. size). 



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