26 GEOLOGICAL MEMOIRS. 



carbonate of lime is secreted and deposited both in the intertubular 

 gelatinous substance (involucral membrane), and in the interior of 

 the elementary cells, together with an occasionally very large amount 

 of starch, so that the whole texture passes into a solid substance. 

 These yl/(/ce are, therefore, in some measure, self-petrifying plants, 

 the vital functions of which, as those of the Corals, remain visible 

 only at the extremities. 



The same structure has been ascertained by Prof, linger to exist 

 in the problematic concretions of the Leitha-limestone, which, in 

 consequence, may be considered to be chiefly of vegetable origin. 

 This limestone has been supposed to represent the remains of reefs 

 in the Tertiary seas ; and this supposition is confirmed by two charac- 

 teristic forms in which this rock occurs. The first of these conditions 

 (occurring in the Sausal Mountains of Styria) has the aspect of a 

 real coral-reef, chiefly composed by stony structures of Sarcinula 

 gratissima^ mixed with some few species of Astrcea and Expla- 

 naria. The second form, intimately connected with the former by 

 transitional characters and by its mode of deposition, is the Nulli- 

 pore-limestone, in the strict sense of the term ; and, apparently 

 formed on a muddy sea-bottom, it skirts the outlines of shoals. 



Prof. Unger thinks that our knowledge of the reefs in the existing 

 seas is still too imperfect to enable us to decide what share in their 

 formation is due to the above-mentioned lithogenous xilgce. 



The presence of genuine reef-forming Corals in the Pannonian basin 

 of the Tertiary period (at 47", and more, N. lat.), while at present the 

 northern limit of such Corals in the Red Sea and Persian Gulf is 

 29° N. lat., may be regarded as a strong evidence of the connection 

 of that basin with these gulfs in Tertiary times. It may be supposed 

 that the warm water of the Indian Ocean, passing over the present 

 Isthmus of Suez, overran the Pannonian Coral- and Algae-reefs, 

 affording them the necessary conditions for their development ; just 

 as the Gulf-stream at the present day acts on a similar marine vege- 

 tation along the western coast of Norway, which is there used for 

 manufacturing lime, as the Leitha-limestone is in Austria. The Leitha- 

 limestone, especially the Nullipore-rock, being of vegetable origin, at 

 least in the proportion of five to one, has been extensively used in 

 Vienna as building-stone for many centuries ; this capital, therefore, 

 may be said to be built of vegetable remains {NulJiporce), as Paris is 

 of the remains of minute animals (Miliolites). 



[Count M.] 



On the Glacier o/Sulden (Vedreti^ del Monte Martello) 

 in Tyrol. By Major de Sonklar. 



[Proceed. Imp. Acad. Sciences, Vienna, December 11, 185G.] 



Major de Sonklar in the summer of 18.00 visited this glacier, 

 situated in the background of the Sulden Valley, bounding to the 

 east and south the jy/a.ssire of the Ortles. The glacier is composed 

 of three })rincipal affluents, 17,154 feet (Austrian) long, and is spread 



