Reéxamination of American Minerals. AZ 
slight differences in the protoxyds. The relation of the oxygen 
of the silica to that of peroxyds in most of the analyses, is as 3 : 2. 
he specimens examined were received from Prof. Silliman, Jr. 
18. The Chesterlite Tale—a Mica. 
_Associated with the Chesterlite, a micaceous mineral is found, 
which has been called tale. It occurs in implanted erystals, in 
minute tuft-like aggregations on dolomite, there is frequently an 
iron stain upon the surface, due to the decomposition of some o 
the minerals with which it is associated, the crystals are seldom 
over a line in diameter. Its chemical composition is that of a 
mica, but owing to the small amount examined it is impossible 
to say positively whether it be muscovite or margarodite, although 
from its association we are inclined to consider it muscovite. 
Silica, > ; : 3 F 45°50 
Alumina, . . et 4 ud 34:55 
Peroxyd of iron, ; : ; ; trace 
Lime, ‘ 231 
Magnesia, - 1:08 
Potash, 5 8-10 
Soda, : : , , : 2°35 
Water and carbonic acid, ; , : 540 
99°29 
A large portion of the lime and magnesia is doubtless due to 
the dolomite with which it is associated. 
The specimen was received from Mr. Thos. F. Seal. 
19. Rhodophyllite, identical with Rhodochrome. 
The violet colored mineral which occurs at Texas, Pa., and 
was circulated among mineralogists as “violet talc,” has been 
erite, he doubtless felt himself justified in considering it a new 
Species. A short time after his results appeared, an analysis of 
thodochrome was published by Hermann ; its identity with those 
of rhodophyllite induced us to reéxamine the latter. 
The results on two analyses are: 
7 2. 
Silica, : ; 33-26 ; ? 33°30 
Alumina, ; ‘ 10-69 : : 10°50 
Sesquioxyd of chromium, 4-78 : ; 4°67 
Peroxyd of iron, ‘ 96 : ; 1°60 
esia, ‘ ‘ 35-93 : : — 
and Potash, ‘ “BB : 
Water, ; ; 1264 : 13°35 
! 99°61 99°75 
* Proc, Acad. Nat, Sci, Phil. yi, 122. 
