i 9 6 Mr. Gregor on a native Arseniate of Lead. 
which lode underlay about two feet in the fathom south : at 
the depth abovementioned ; this lode fell in, or formed a junc- 
tion with another small lode or vein to the south, and when 
the junction took place, this lead ore was found. The veins 
of it are, in general, from six to ten inches wide, and they 
diverge on going west. Some particles of this lead ore have 
been found in the southern part, after the separation of the 
lodes ; but the northern lode does not contain any, until the 
junction takes place. This ore is intermixed with some native 
copper, very rich gray copper, and black copper ore, and 
some is mixed with quartz. The walls of both veins are 
killas. 
II. Description. 
This mineral is regularly crystallized. The form of its 
most perfect crystals is an hexaedral prism ; they are of dif- 
ferent sizes, from one tenth of an inch in diameter, to the size 
of a hair. The longest which I have seen, do not exceed 
three tenths of an inch in length : these terminate in a plane, 
at right angles, with the axis of the prism ; but the crystals of 
a smaller size are frequently drawn out into a very taper acu- 
mination, which appears to be a six-sided pyramid. A num- 
ber of smaller crystals are often closely packed together in 
bundles, which are bent in different directions, and terminate 
in a point. The larger crystals, either stand alone, or adhere, 
on their lateral planes,'to the gangue, or are confusedly matted 
together in a mass. 
Some of them are hollow, as if an internal nucleus had been 
destroyed : and sometimes this internal nucleus overtops the 
external lamince. The gangue is a white quartz, which fre- 
