M. Studer on the Geological Structure of the Alp9^ 153 



Alps {lIochgehirg8kalk\ reposes on the mixed formation ; it 

 generally presents enormous escarpments turned towards the 

 gneiss masses, and the large limestone wedges which arc en- 

 tangled in the mass of the gneiss are generally formed of it. 

 The beds of limestone are distinctly separated, and the rock 

 often passes almost into slate. Its colour varies from grey to 

 black ; it is as friable as glass, and, with the exception of some 

 belemnites, it contains no petrifactions. In the Hasli valley, 

 this limestone formation is covered by a thick series of brilliant 

 black slates, which, at Planplatten, above Meyringen, contain 

 considerable deposits of red oxide of iron and iron in grains. 

 In the vicinity of these ferruginous repositories, the slates fre- 

 quently include prominent nodules and ammonites, which evi- 

 dently belong to different members of the oolitic formation, 

 as, for example, at Erzeck, and near Unterheid, opposite Mey- 

 ringen. Belemnites are of rarer occurrence. 

 -•■ Chalk Series. — The cretaceous formation succeeds these 

 black slates, and when these are awanting, it follows the 

 limestone of the high Alps. As in Southern Europe, this for- 

 mation is distinguished by peculiar characters, and likewise 

 by the extent and thickness of many of its subdivisions, which 

 confer on it considerable importance in the composition of 

 the calcareous Alps. A fact worthy of attention is, that fre- 

 quently, and more particularly in the first limestone chain, 

 the Alpine limestone is separated from^the chalk by a series 

 of rocks having the greatest analogy to the mixed formation 

 of which we have spoken, and consisting of beds of quartzite, 

 of brilliant variegated slates, and of crystalline and dolomitic 

 white limestones. This is observable on the Gemmi above 

 Kandersteg, at the bottom of the valley of Lauterbrunnen, on 

 the Wengern-Alp, and on the Faulhorn ; and perhaps we may 

 include under the same head the beds of iron in grains, and 

 the black slates of Planplatten. 



The arenaceous black limestones, the quartzose sandstones, 

 and the rough slates, which repose on the limestone chains 

 that are nearest to the gneiss groups, and which form the 

 largest portion of the mountains situated on the exterior of 

 these latter, seem to belong to the most recent layers of the 

 Alpine cretaceous formation. The most abundant fossils there 



