224 J. B. Pearse on Minerals of the Chlorite Group. 
We may reject at once from the above list chonikrite (6), and 
pyrosclerite (12) as impure. The kimmererite of Hartwall and 
Garrett (11) not being quite pure, and differing but slightly from — 
von Kobell’s pyrosclerite (9) might be referred to the latter, as _ 
Dana has done. But as pyrosclerite (9) differs by only one atom 
_ Our critical examination of the above series of minerals lim- 
its their number to four, viz. Nos. 2, 8, 6, (7) and 8, whieh are * 
here presented as distinct varieties, together with the formule of Me 
olivine, augite, and serpentine, for the sake of further diseussio® 
Nos. SiO, Al,0, Mg,0 H,O : 
2. Grastite, 5 2 9 8 Pearse and Hermant 
3. Chilorite, 6 2 10 8 Many analysts. 
6. Rhodophyllite, z - 12 10 Genth and Pearse. ; 
8. Kammererite, 8 2 14 10 Smith & Brush. 
ugite, 1 1 : 
Olivine, 1 2 : 
Serpentine, 2 3 2 : 
A comparative study of the above shows the following ot ‘ 
markable differences between these varieties of the chlorite gt0UP’ 
Grastite + augite = chlorite. 
Grastite + serpentine = rhodophyllite. ; . 
Grastite + olivine + serpentine == kammererite. oe 
In other words, the differences of composition agnor eet 
bers of the chlorite group are the simpler minerals etofore 
with them in locality, or from which they have been hereto! es 
assumed to be derived. e 
My apology for a new name is that not one of those heretofore prop i: 
any member of this group is applicable, oe 
