902 The American Naturalist. [October, 
field,” consist of an inner uniaxial hexagon surrounded by six segments 
extinguishing parallel to their edges and showing a biaxial interfer- 
ence figure. The mineral is monoclinic and is twinned like the clino- 
chlor? from Texas, Pa. It is associated with quartz, lepidolite and 
tourmaline, and has probably been derived from the latter by altera- 
tion. An analysis of carefully selected material gave: 
SiO, ALO, Fe,O, CaO K,O Na,O LiO H,O F Total O—F 
34.00 45.06 45 04 14 .19 4.02 14.96 .46—99.32—.19—99.13 
This corresponds to the formula Li [AI(OH),], (SiO,),. The density 
of cookeite is 2.675. 
The results of an examination of zunyite from the Charter Oak mine, 
at Red Mountain, Orange Co., Colo., and of zenotime from Cheyenne 
Mountain, El Paso Co., in the same State, have recently been commu- 
nieated by Penfield.” The zunyite occurrence is five miles north of 
the original occurrence of the mineral first described by Hillebrand. 
The mineral is in little tetrabedrons scattered through an altered por- 
phyrite. An analysis of these gave: 
SiO, ALO, Fe,0,Cl F H,O P,O, CaO Na,O Total O—CI&F 
24.1 157.20 .61 2.62 5.81 11.12.64 11 .48 —102.70—3.03—99.67 
corresponding to [AI(CLF.OH),], Al, (SiO), Zunyite is found also 
in the mine as a white pulverulent mass resembling kaolin, but which 
consists of tiny octahedral crystals. The xenotime was from the 
tysonite locality described by Hidden" in 1885. It was a single fresh 
erystal of a brown color, implanted on a gangue of quartz and feldspar. 
Its density was found to be 5.106, and its composition : P,O, — 32.11; 
Xt Er*-07.10; lou. — 15. 
In the crystalline dolomite of Canaan, Ct., Hobbs" has discovered 
a rose-colored tale, that is noticeable for its large percentage of calcium 
and aluminium. Its analysis yielded: 
SiO, ALO, MgO CaO FeO MnO H,O ‘Total 
61.48 3.04 22.4 419 JI tr 5.54 — 100.56 
The density of the mineral is 2.86. It is optically negative, and its 
axial angle 2 E is 15° 30’. 
. In a recent Bulletin of the United States Geological Survey, Mel- 
A r. Jour. Sci., XLV, 1893, p. 393. 
un . 201. 
"XLIV, 
"Ib. XLV, 1898, p. 396. 
» Ib. XXIX, p. 249. 
