24 A. R. Leeds—Contributions to Mineralogy. 
O ratio for B, Siand H = 1:3:1, Bemreeponting | to he hydrous 
silicate Me? Si? + 2H = SiO, 60°8, MgO 27-0, H?0 12 While 
closely ee tale in its physical ae ane pseudo- 
morp r pectolite is near sepiolite in its chemical composi- 
tion. 
Ill. Leucaugite from Amity, N. Y. 
Occurs in rounded, undefinable prismatic crystals and coarse 
grains, along with seybertite, i in pi te. 
H.=5%5. G.= 3-26. Luster vitreo-resinous, bright on 
cleavage surface ; dull on fracture ; color light-orown ; streak 
white; translucent in thin splinters ; fracture coarse sranular ; 
very brittle ; B.B. fuses slightly on the edges becoming grey- 
ish-white ; feeble iron reaction with mierocosmic salt. 
It resembles in color and general appearance the spinel occur- 
ring along with Senne and ac at Warwick, Orange 
Co., N. Y. It is likewise almost identical in composition, 
color, ete., with ‘he leucaugite from Bathurst, W. Canada, 
described and analyzed by Prof. T. S. Hunt (Dana’s Min., 5th 
ed., pp. 216 and 218). Composition 
O ratio. 
SiO, 50°05 =. 26-698 : 
Al,O, 716 -3°337 { s0-080 3 
Fe,0, 0°56 0°504 
MgO 1448 5792 ; 
CaO iG 7391 sistas oes 
H,O 166 1°46 
99°54 
This composition is that of a Netter of lime and magnesia, 
with some of the silica replaced by alumina. It is, therefore, 
an aluminou SP roxene of the formula (Ga, Mg) (Si,41 3), which is 
the formula o Tasicguiteta. 
IV. Mineral associated with Corundum and approaching 
Ripidolite 
Occurs at the Lesley farm (corundum locality), now owned 
by Messrs. Pusey & Ball, in Newlin Township, Chester Co., 
es open ap in a mass of about 30 lbs. at the borders of 
ng mass of corundum, of which about 60 tons (Jan., 
1873) have now been laid bare. In the specimen from which 
the ma e analysis was — the corundum is 
bordere d by a soft mineral, which Dr. Isaac Lea pronounces 
“lesleyite” (App. Dana’s Min., p- 18). It contains both lithia 
and potash. As it recedes from the corundum, the lesleyite 
ler = character, becoming white and diminishing in its pot- 
entage. e mineral analyzed contained no potash 
rr but abundant lithia. 
