566 The American Naturalist. [June, 
and appended to it are twelve plates containing seventy-two micro-pho- 
tographic reproductions of their sections. 
New Minerals.— Geikielite.°—This mineral was found as pebbles 
in the gem washings near Rakwana, Ceylon. It is essentially a mag- 
nesium titanate, MgTiO,, corresponding to the calcium compound, 
perofskite. The mineral is bluish-black and opaque, with a brilliant 
lustre, and possessing two cleavages at right angles to each other. Its 
density is 3.98 and hardness 6.5. In thin section it is translucent 
with a purplish-red tint, and in converged light it shows a uniaxial 
re. 
Baddeleyite,” also occurring as pebbles in the above-mentioned 
locality, is a black substance with a density of 6.02 and a hardness of 
6.5, thus strongly resembling columbite. Under the microscope small 
fragments are seen to be dichroic in greenish-yellow and brown tints, 
and to possess a biaxial symmetry. The crystallization is thought to 
be monoclinic, though only a few plans could be detected on the speci- 
men. In chemical composition the substance is zirconia ZrO,. 
Folgerite, blueite and whartonite are all nickel-iron-sulphides from 
the Sudbury nickel mines at Algoma, Ontario. Emmens” describes 
the first named as a massive, bronze-yellow substance, with a grayish- 
black streak, a density of 4.73 and hardness 3.5. Its composition (Fe 
= 33.70; Ni = 35.20; S = 31.10) corresponds to Ni Fe $, 
The blueite is also massive. Its color’is olive-gray or bronze ; its 
streak black, density 4.2 and hardness 3-3.5. Its analysis yielded Fe 
= 41.01; Ni = 3.70; S = 55.29, corresponding to pyrite with a 
thirteenth of the Fe replaced by Ni. Unlike pyrite, however, it dis- 
solves easily in nitric acid, without the precipitation of sulphur. 
Whartonite differs from blueite in containing more Ni. Its composi- 
tion is Fe = 41.44; Ni — 6.27; S= 52.29, corresponding to (Fe Ni) 
8, in which Fe: Ni=7:1. Its hardness is 4, density 3.73, and color 
and streak like those of blueite. 
Hauchecornite is another nickel mineral. It is described by Scheibe” 
from the Friederich mine in the Hamm mining district, Germany. It 
is found in bronze-yellow tetragonal crystals, with a hardness of 5, and 
4 density of 6.4. It is thought to have the composition corresponding 
to the formula Ni (Bi. Sb. S), though analysis yields discordant results. 
Cuprocassiterite was described by Ulke” from the Etta mine, South 
1 Fletcher: Nature, Oct. 27, 1892, p. 620. 
11 Jour. Amer. Chem. Soc., Vol. xiv, No. 7. 
12 Jahrb. A. preuss. geol. Landeranst, 1891, p. 91. 
13 Proc. Amer. Inst. Min. Engineers, Feb. 1892. 
