1885. ] Mineralogy and Petrography. 885 
tion c>b. No satisfactory sections parallel to the clinopinacoid 
for the determination of the a ray were obtained. In converged 
polarized light sections parallel to «œ P 3 showed one optical axis 
somewhat out of the field, so that only a dark brush was seen to 
pass as the stage was revolved. The exact measurement of the 
extinction in sections parallel to the clinopinacoid was not easy 
on account of the fibrous character of the mineral. Different 
values were obtained on different fibers, the largest and most fre- 
quent being from 22°- 
There can therefore be no > doubt that this mineral is really mono- 
clinic in spite of its chemical composition and general resemblance 
to the orthorhombic anthophyllite. This fact is of interest in con- 
nection with the observations of Des Cloizeaux on an exactly sim- 
ilar mineral from Königsberg and Greenland, for which he first pro- 
posed the name amphibole-anthophyllite.’. Groth has remarked 
that a considerable proportion of the minerals commonly called 
anthophyllite are probably monoclinic in their crystallization. 
Zeparovich has recently noted the occurrence of amphibole- 
anthophyllite at Sinekbele i in Passeyr—G. H. Willams. 
New PLANES on HorNBLENDE Crystats.—In Vol. vu of his 
Materialien zur Mineralogie Russlands, 1881, N. von Kokscharow 
enumerates eighteen forms as heretofore observed on the mineral 
hornblende. Of these five only b (vP &) elo P3), M (oP), u 
(co P3) and a (œ P 3) belong to the prismatic zone. One other, 
g (oo PZ) was added by Franzenau from his studies of the horn- 
herd from Aranyerberg, in Hungary. 
Certain dark-green crystals of pan e (pargasite) occurring 
at East Russell, St. Lawrence county, N. Y., although having but 
few lusterless terminal planes, possess in the prismatic zone a 
wealth of forms which has never before been observed on this 
bic=.548258: 1: .293765 — &= 75° 2’, the angle between 
these planes and the clinopinacoid b are 
measured calculated 
For x 159° 23’ 159° 18/ 48/7 
For y 165° 8 164° 54’ 20/7 
On these crystals, as usual, the planes a, n, M,’e and b are the 
commonest, g and x are, however, not uncommon; y was ob- 
served on only one = i where it was bright and well del- 
oped.—G. H. Williams. 
? ; Nouvelles Recherches sur les propriétés optiques des cristaux, 1867, p. 114. 
p tineraliensaminlung der ouran Strassburg, 1878, p. 228. ‘Tabellarische 
bs Dt de a 1882, p. I 
os,” 
P iy fiir Krystallographie, vrt, 1883, p. 568. 
