182 Scientific Intelligence — Geology. 



strata {F alien- Gehirge)^ crystalline slate mountains, and central 

 mass mountains of upper, middle, and lower section. 



10. The mountains with folded strata of this sort, however, are 

 not always distinguishable from those originating in lateral pressure. 



11. Of especial importance in judging of the relative age of the 

 mountains — besides the distinction of elevated and non-elevated beds 

 brought forward by E. de Beaumont — is the fixing of the mountain 

 chains as lines of separation between deposits during determined 

 periods ; recognizable by dissimilar characters in the series of sedi- 

 mentary formations on two or more sides. 



12. The volcanic mountains are distinguished from the plutonic, 

 consolidated within the earth, both by their external form and by 

 their mineralogical conditions. The first form superficial, the 

 second form subterranean, cones of eruption. The section of these 

 last exhibits (for example) the so-frequently referred to granite-ellip- 

 soids. Both, however, Gil up also narrower fissures, in which they 

 are then mostly crystallized somewhat otherwise than in the great 

 principal masses. 



4. 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 Wes- 

 terwald and the Lower Rhine, as also that of the Vogelsberg, belong 

 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 suharata, Bronn, Cerithium mar- 

 garitaceum, 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 ela- 

 borate 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.- — Quarterly Journal of the Geological 

 Society, vol. vii., No. 28, p. 118. 



6. On an extensive Bock- Formation of Siliceous Polycystina 

 from the Nicohar Islands. By Prof. Ehrenberg. (Berlin Mon- 

 atsbericht, 1850, p. 476-478. Leonhard u. Bronn^s Jahrbuch 

 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 serpentinous 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 



* Palaeontographica, II. 2. 



