20 
The mineral is optically negative and its elongation is also negative. 
The acute bisectrix makes an angle of 16- degrees with C in the obtuse 
angle 0 . 
a = 1-513 ± 0-001; & = 1-519 ± 0-001; y - 1-520 ± 0-001. 
Thus the birefringence (7 — a) = 0*007 is weak. 
BARITE FROM MADOC TOWNSHIP, HASTINGS COUNTY, 
. ONTARIO 
Hastings county is well known from the handsome specimens of green 
fluorite it has furnished many American museums. The encrustation of 
crystalline barite, ^which generally covers the fluorite, does not, as a rule, 
Figure 6. Orthographic and elinographic projections 
of barite from Madoc township, Hastings county, 
Ontario. 
