Mineralogy and Petrography. 529 
metals, They are found in the eleolite-syenite veins of Norway.! 
—Cliftonite. With reference to certain little cubical crystals of 
graphite (?) found in pieces of an iron meteorite from Youndequi, 
Australia, Fletcher? states that Haidinger as early as 1846 described 
crystals of graphite, which he regarded as pseudomorphs after 
pyrite. Since pyrite does not occur in meteorites, and since, more- 
over, these little graphite pieces are entirely surrounded by metallic 
iron, Fletcher thinks that their shape must be original, and that 
this substance is truly regular in crystallization. 
CRYSTALLOGRAPHIC News.—It has been known for a long time 
past that the natural conclusions to be drawn from the Bravais- 
Mallard theory of cleavage planes and erystal structure, based upon 
the point system of explaining crystallization, have not been borne 
out by the facts. As a consequence of this theory it is demanded 
that the planes of easiest cleavage in a mineral should be parallel 
to those planes which are most commonly present on it and best 
developed. This is known, however, not to be the case. Sohncke?* 
explains how these difficulties can be met by modifying the theory 
of the point system, as pointed out by him in recent* papers. —The 
same subject is further discussed by Wulff,> who takes up the dif- 
ferent crystallographic systems in detail, describes in terms of the 
eory the inner structure of minerals crystallizing in each, and 
orms on the crystals examined, among them the new forms 4 Pœ, 
2 P35 P5,-3 P36 P 3 and3 Pj (a: 6: ¢ = 1.2657 : 1 : 6354 
pix 89° 51’). The optical angled measured in oil is 74° 21’ for 
sodium light, and the first bisectrix is inclined 51’ to the c axis, in 
the acute angle 3. An analysis of the mineral gave Si O, = 37.89, 
Ca O 3. H Oiee 
from Mt. Avala, near Belgrade in Servia, have been carefully meas- 
ured by A. Schmidt.” He finds on them: trapezohedral forms so 
largely developed as to determine their habit. To the forty-eight 
aine already described as occurring on the mineral, Schmidt adds 
m new ones, viz.: } P2, 4 P2, 6, P$, 2 P4, 2 P$, 2 P$, ¢ PR 
$ P3, 4$ P$ and & P3.—The negative deltoid dodecahedron- > 
I régger : Geol Fö REN . 
2 ; - Fören. Föhr., 1887, ix., p. 247. a 
3 Miner Magazine, J uly, 1887: and Zeits. f. Kryst., xiii., 1887, p. 383. 
use. f. Kryst., xiii., 1887, p. 209. 
16, p. 
. f. Kryst., xiii., 1888, p. 503 
6 p . . 3 . int 
; Zeita, f. Kryst., xiii., 1887. 4 150. 
+f. Kryst., xiii., 1888, p. 433. 
