362 Scientific Intelligence — Mineralogy. 



chelkalk. They have also been described by DrDunker as occur- 

 ring in the Wcalden of Germany ; by Braun, in the marl-slate of 

 the Zechstein near Frankenberg ; and by others, in the tertiaries 

 of Austria and of the south of France. 



In all these different localities the u hopper-shaped " crystals 

 (or cubes with hopper-shaped impressions) are the most frequent, 

 and are the same forms of salt which are produced by gradual 

 evaporation, whether in salt-pans or on a sea-shore. The materials 

 of which these pseudomorphs are constituted vary with the com- 

 position of the adjacent rocks, and are, in different localities, marly 

 limestone, dolomitic marl, gypsum, quartz (more or less pure), 

 sandstones of many kinds, mica, and brown spar, the last two 

 often disposed only round the edges. In the first-mentioned paper, 

 and in some by Hausmann and Nbggerath on the same subject, 

 will be found much valuable and suggestive matter connected 

 with both the chemical and geological aspect of the subject. — 

 (Quarterly Journal^ of the Geological Society, vol. ix., No. 35, 

 p. 187.) 



7. On Matlockite ; by C. Rammelsberg. (Leonhard u. Brown's 

 N. Jahrb. f. Min. u.s.w., 1853, p. 173 ; Poggend. Annal., 

 lxxxv., p. 141 et seq.) — The new mineral, Matlockite, is very 

 similar in external appearance to Corneous lead (murio-car- 

 bonate of lead, Blei-hornerz), and, together with the latter, it has 

 been found associated with earthy galena, at the deserted 

 Cromford mine, near Matlock. Both are very rare. 



Compact fragments of the Murio-carbonate are transparent, 

 colourless or yellowish, lustrous, and pretty generally cleavable in 

 three directions at right angles to each other. Brooke* and Krug 

 von NiddaJ describe the crystals of this mineral. Rammelsberg 

 found its specific gravity to be 6*305. In powder it was in some 

 degree decomposed even by cold water, chlorite of lead being set 

 free. Its analysis is given below. 



In Matlockite a single but very perfect plane of cleavage has 

 been observed. This mineral has been recognized as a basal chlo- 

 ride of lead. The specific quantity of the powder is 5*3947. Its 

 analysis is — 



Matlockite. Blei-hornerz. 



Chlorine . . 14-12) ,,„, Carbonic acid . 7"99 



Lead . . . 41-50 J Oxide of lead . 40-46 



Lead . . . 41-50 \ .. ™ Chlorine . . 12-97 



Oxygen . . 2-88 ] 44 6 * Lead . . . 37'96 



100-00 99-38 



— (Quarterly Journal of the Geological Society, vol. ix., No. 35, 

 p. 24.) 



* Poggendorfs Annalen, xlii., p. 582. 



% Zeitschrift d. Poustch. Geol. Gesellschaft, vol ii., p. 126. 



