Geological Society. 67 



Upon this system of Jura limestone there are small patches of iron 

 and green-sand at Ratisbon and elsewhere. In this deposit, asso- 

 ciated with argillaceous marl, are found the pisiform iron ores, or 

 Bohnerz of the Germans, concretionary masses of siliceo-calcareous 

 millstone, with many univalve shells and corals (Natheim), and 

 beautifully zoned, chalcedonic nodules, or kugel jaspis, with echini 

 and microscopic shells (near Basel). • 



The author agrees with Mr. Schiibler that it is essential to distin- 

 guish this deposit of Bohnerz from those alluvial accumulations with 

 iron ore made up of the detritus of older rocks, and in which are 

 found the bones of many extinct quadrupeds. (Kanderu, Haiberg near 

 Tutllingen, &c.) 



The Alpine chain south of the tertiary basin of Bavaria is consti- 

 tuted of materials nearly the same as in its range through Austria; 

 viz. 1. A base of red-sandstone and conglomerate. 2. Lower lime- 

 stone with fishes (Seefeld). 3. Gray sandstone and shale with salt 

 and gypsum. 4. Gray dolomite and oolite. 5. Sandstone of Vienna, 

 which though thin and obscure at Salzburg and Sonthofen, expands 

 into a vast formation in its westward range into the Voralberg. 

 6. Green-sand, filling cavities in the Vienna sandstone, from which 

 it is separated by conglomerates made up partly of Alpine limestone, 

 but chiefly of primary rocks, which are not found in situ nearer than 

 the Black Forest. The author conceives this conglomerate to be of 

 the same age as those at the base of the Gosau formations, and in 

 the Allgau; and he further identifies with it the Nagelfluh of Switz- 

 erland, which, although hitherto considered tertiary, he places in the 

 lower green-sand ; and as proofs of this he cites the existence of a 

 similar conglomerate or Nagelfluh on the summit of the Voisons near 

 Geneva, and also near Saanen, where it overlies and is united with 

 what he considers to be the equivalent of the Vienna sandstone. 



The green-sand of the Allgau consists of marls and calcareous sands 

 of various colours containing plants, with here and there subordinate 

 masses of true green-sand, having some characteristic fossil shells of 

 that formation, and iron ore. 



For the details of the tertiary rocks of Bavaria the author refers to 

 his last work (Geologische Gemalde von Deutschland). In speaking 

 of the vast alluvial accumulations which encumber this basin, he re- 

 marks that the debris are all primary near the primary chain of 

 Bohemia, and secondary on the flanks of the Alps or Jura. Erratic 

 boulders of large size are spread out in lines, and extend to some 

 distance in front of the mouth of the valley of the Rhine ; whilst lesser 

 detritus only is found at the debouchure of the Inn. According to the 

 author the elevatory forces which so greatly affected the western Alps 

 must have operated less powerfully upon the eastern prolongation of 

 these mountains. 



Alluvial marl, as in Austria, covers the sides of the Danube in its 

 course through Bavaria ; and all the lower regions of the latter country 

 offer innumerable proofs of various changes during the alluvial period 

 in the successive drainage of lakes, and in the alteration of the course 

 of rivers. 



K 2 Friday- 



