70 Capt. Bonnycastle on some of the &e. 
some convulsion as they are much broken and irregular, dif- 
fering also in their aspect from those on which they repose, 
aud passing by exposure to the oxygen of the air, or some 
other operating cause, into a dull whitish (argillaceous) grey 
looking substance. 
Calcspar commonly is in conjunction with the barytes, and 
is sometimes red orof a pale flesh colour, but the whole spe. 
cimes is very frequently much decomposed. Nodular masses 
of this barytes, coated by argillaceous lime of a dirty light 
brown colonr, and of the size of a cocoa nut, are also some- 
times found on the surface of the exposed beds. 
I have been particular inthe examination of this mineral, 
because I suppose that it is the substance which has long 
passed at Kingston under the designation of tremolite. Its 
obvious great specific gravity might have prevented this mig- 
take. , 
Structure bladed & radiated ; the plates or blades very loag 
and intersecting in broad rays, leaving interstices. Fracture 
crystalline, and, in the direction’ of the rays, lamellar and 
shining; across them uneven, powdery and dull. Lustre, fine 
white and shining, rather vilreous. Poqder, white, & harsh, 
and also breaks into little long spangles on slight trituration, 
Streak, white. Scratched by fluor spar and in some places, 
by the nail. Not affected by the acids nitric, muriatle nor 
sulphuric, ncitherin mass, powder nor spangle. Alone on 
charcoal it is very difficult of fusion ; in a thin lamina it turns 
white, and transparent on cooling, at the first blast ; on the next 
turns again lime white, and gives out an intense and beautiful 
white light, after which it separates, swells a little, and fuses 
into an irregular dull, Uut fine while, enamel, which when cold 
and placed on the tongue, gives the peculiar disagreeable taste 
of sulphuretted hydrogen and after a few hours becomes 
soft and powdery 
Ant; 
