and its associates on Lake Supertor. 253 
No. 52. SHELDEN AND CoLUMBIAN MINE. In cavities in a 
brown and green amygdaloid lie, 1. Quartz in well shaped 
prisms. 2. Calcite; Quartz. This second quartz is in small 
and very much distorted crystals, which are often partially im- 
bedded in the calcite, and are also often planted on the older 
quartz, from which they can be easily removed without fracture. 
o. 58. Huron Mine. 1. Quartz with more or less crys- 
talline structure. 2. Copper moulded on the quartz and filling 
cracks and interstices in it. 
No. AGGED AMyGpALorD. Sr. Mary’s. In the rock 
(see No. 85), some of the smaller cavities contain, 1. Orthoclase 
as a thin crystalline lining. 2. Calcite filling the interior. 3. 
os agg mineral penetrating and apparently replacing the 
cite, 
In a larger cavity occur the following : Se 
No. 55. 1. Analcite crystals inch to 2 inches in diameter, 
much reddened. 2. Orthoclase; small crystals on the analcite. 
. Clay? a soft white mineral, apparently the result of con- 
tinued decomposition of the analcite under conditions unfavor- 
able for the formation of new silicates as feldspar. 
No. 56. “ Anctent Prr” BED. Dovenass Location. 1. 
Epidote forming a crystalline lining of a cavity. 2. Quariz 
filling the interior. 
o. 57. SuLPHURET (Fissure vein) HURON sien The 
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each side. 2. Quartz in two symmetrical comby bands on the 
dolomite and in thin seams in the dolomite connected b cross- 
Seams with the quartz-comb. 3. Chalcocite, black—bluish-black 
with distinct cleavage. Tt resembles the pseudomorphous chalco- 
cite of the Lac la Belle mine. Bornite occurs sprinkled th ough 
the chaleocite in minute specks; in places it predominates, 
— 
ese sulphurets form the central member, and bunches of 
them are often surrounded by the older members, giving the 
Note.—It is in another portion of this vein that the arseniurets, whitneyite and 
domeykite are found. 
have attempted to bring the foregoing observations into 
serve for a check upon the imper 
Copper anp Caxtcire.—In many of the ms 
Calcite crystals are found enclosing copper, ub 
instances in which 
is difficult and 
* 
