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GEOLOGICAL MEMOIRS. 



Ehrlich, on account of the presence of very characteristic fossils, 

 ascribes an eocene age to the nummulitiferous sandstone near Mattsee, 

 not far from Salzburg. 



The nummulite-beds of Switzerland have been examined by Brun- 

 ner and Rutimeyer ; those in the Basin of the Gironde by Raulin ; 

 and very valuable general remarks on this Formation have been sup- 

 plied by Boue and Murchison. [T. R. J.] 



On German Tertiary Formations. By F. Sandberger. 



[Leonhard u. Bronn's Jahrbuch f. Min. u.s.w. 1851, p. 177.] 



Tertiary formations of the age of the Mayence Basin are widely 

 distributed in Germany. That the Brown-coal formations of Wester- 

 wald and the Lower Rhine, as also that of the Yogelsberg, be- 

 long to this period is easily proved by their fossil shells and plants. 

 With regard to their Vertebrata, von Meyer long since supplied the 

 necessary proof. Moreover the Brown-coal formations of Miesbach 

 in Upper Bavaria contain Cyrena subarata, Bronn, Cerithium marga- 

 ritaceum, and other characteristic forms of the Mayence Basin. The 

 Vertebrata of the Molasse of Switzerland agree also with those of the 

 last deposit, and in respect to North Bohemia, the elaborate work of 

 von Meyer and Reuss* affords also a similar result. The Mayence 

 Basin is moreover the type of a whole series of such deposits, as is 

 the London Basin with respect to the old-tertiary clays of the Baltic 

 plain. [T. R. J.] 



On an Extensive Rock-formation of Siliceous Polycystina 

 from the Nicobar Islands. By Prof. Ehrenberg. 



[Berlin. Monatsbericht. 1850, p. 476-478. Leonhard u. Bronn's Jahrb. f. Min. 

 u.s.w. 1850, p. 237.] 



Hitherto Barbadoes only has afforded rocks with Polycystina. 

 The Nicobar Islands lie in nearly an equal latitude with it, but in the 

 East, instead of the West Indies. They consist of syenitic and ser- 

 pentinous porphyry or gabbro-rock with pyrites, but without any 

 recent volcanic ejectments, on which, to the height of 2000', lie clays, 

 marls, and calcareous sandstones rich in Polycystina. The author 

 has already obtained from hence 1 00 species, which are partly iden- 

 tical with the 300 species from Barbadoes. The islands Car Nicobar 

 and Comarta are especially remarkable in this respect, and on the latter 

 exists a hill 300' high, throughout which the Poly cystina-clay occurs. 

 A light meerschaum-like clay and shale (tripoli, polishing shale) found 

 there and at other places is composed nearly altogether of these 

 bodies mixed with many Spongolithes. These clays are generally 

 traversed bv lignitiferous deposits and by syenitic gravels. 



[T. R. J.] 



* Palaeontographica, ii. 1. 



