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GEOLOGICAL MEMOIRS. 



On the Elevation of the Coast of Sweden. By M. Nilsson. 



[Leonhard u. Bronn's Neues Jahrb. f. Min. u. s. w. 1850, p. 477 ; and Biblioth. 

 univ. Geneve, Sc. phys. 1851, p. 149.] 



In a work on the Existence of Man in Scandinavia previously to the 

 historic age (Forhandl. Skandin. Naturf. 4. mode i Christiania, 1844, 

 Chr. 1847, p. 93-109), the author furnishes some interesting data 

 relative to the elevation of the land in that region. A rock, named 

 Gudmandz Schare, in the harbour of Fjellbacka (Lat. 58° 35'), has 

 offered opportunities of careful examination ; and hence it has been 

 established that in 1532 the rock was 2 feet below the surface of the 

 sea, — in 1C62 it was 7 or 8 inches above the surface, — in 1 742, 2 feet, 

 — and in 1844, 4 feet above water. Thus it has risen 6 feet in 300 

 years — or at the regular rate of one foot in fifty years. [T. R. J.] 



On Arkansite. By A. Breithaupt. 



[Poggendo-rfF s Annal. d. Phys. t. lxxvii. pp. 302 et seg.; and Leonhard u. Bronn's 

 N, Jahrb. f. Min. u. s. w. 1850, p. 846.] 



The new mineral Arkansite*, discovered by Dr. Shepard near the 

 Hot Springs f, Arkansas, U.S., is described as being peculiarly in- 

 teresting in a crystallographic point of view. The following are its 

 chief characteristics : — 



Externally the lustre is always semi-metallic, somewhat approach- 

 ing a metallic diamond-lustre. Externally the surface of the crystals 

 have a more or less metallic appearance. Colour iron-black. Streak 

 dark ash-grey. Quite opake. The primary form, as seen in the 

 crystals, appears to be a brachyaxial, rhomboidal pyramido-hedron. 

 The author observed several combinations, but a detailed description 

 of them cannot be well understood without the figures. The clea- 

 vage is not distinct. Fracture uneven. Compact masses of this 

 mineral form a rather loosely coherent, granular compound. Hard- 

 ness=7| to 8. Specific gravity =3* 952. 



Arkansite is found mixed with greyish-white quartz ; and both 

 have unmistakeably the appearance of occurring in veins. 



[T. R. J.] 



On the Tchornoi Zem of Russia. By Prof. Ehrenberg. 



[Monatsbericht Akad. Wissensch. Berlin, July 1850, pp. 268 etseg.; and Biblioth. 

 Univ. Geneve, April 1851, Sc. Phys. p. 329.] 



The Tchornoi Zem or Black Earth of Central Russia, covering more 

 than 60,000 geographical square miles, and of extreme fertility, — 

 supporting more than 20,000,000 of souls, and giving rise to an 

 annual exportation of about 20,000,000 hectolitres [=55,000,000 



* See Quart. Journ. Geol. Soc. vol. vii. part 2. p. 90. 



f [This mineral occurs also in geodic masses in the Silurian slates near Trema- 

 doc, North Wales. — Transl.] 



