ARTICLE III. 
NATURAL HISTORY OF ROCKWOOD PARK. 
Rocks and Minerals of Rockwood Park. 
By G. F. Matthew. 
Abstract of Address given December 6, 1910. 
Minerals. — Owing to the frequent exposure of rocky ledges 
in various parts of the Park, several kinds of minerals and rocks 
have been noticed, and some have been mined and others quarried. 
Black Lead or Graphite. — Many years ago a mine of black 
lead was worked by the Gilberts at Lead Mine Point — a low 
point of land on the eastern side of Lily lake near its outlet. 
The mineral mined here was of a kind suitable for stove polish 
and for foundry facings, but not for purposes to which the finer 
grades of graphite are applied. 
Ophicalcite or Verd Antique. — The translucent green variety 
of serpentine occurring in magnesian crystalline limestone, is 
found in the limestones at the west end and the north side of 
Lily lake. The best examples observed were from limestone 
a little west of the western boundary of the park. 
Common Serpentine. — This kind of serpentine which is the 
result of metamorphism in igneous rocks, is present in a vein 
or dyke of such rock that cuts the quartzite at the southwest 
side of Look-out hill, just back of the northern cove of Lily 
lake. It is a dark, gray rock mottled with spots of lighter 
gray, giving the appearance of a snake’s skin, hence the names 
“Ophite,” or “Serpentine,” by which it is known. 
Tremolite. — This is a light gray, fibrous, or bladed mineral, 
found in the magnesian limestones on the Adelaide road, that 
would extend across the northern end of the park by Dark lake. 
It may occur in any of the magnesian limestones, found in the 
area of the park. 
Stalactite and Stalagmite. — These are varieties of lime or calcite 
found in caverns in limestone rock; examples have been found 
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