326 
DESCRIPTIVE MINERALOGY. 
and granular varieties of garnet, tabular spar, green coccolite, and occasionally with crystal¬ 
lized hornblende. This locality was first described by Mr. A. E. Jessup.* 
The composition of this colophonite, according to Mr. H. Seybert, is as follows: t 
Silica,. 38.00 
Lime,. 29.00 
Protoxide of iron,. 25.20 
Alumina,. 6.00 
Water,. 0.33 
A similar locality exists in the town of Lewis, about ten miles south of the village of Iveese- 
ville. J’lie'specimens can scarcely be distinguished from those obtained from Willsborough. 
It is, like that just described, an immense deposit of colophonite in large grains, associated 
with, and apparently passing into, massive garnet of various colours. It is also associated 
with tabular spar, which, as well as the garnet, is very abundant. 
Several varieties of garnet are found in great abundance at the celebrated Rogers’ rock. 
These, however, constantly pass into each other by almost imperceptible shades, and some¬ 
times several of them are found in a mass of one or two feet in diameter. In some parts of 
the deposit, the garnet is in the form of red grains and irregular masses, associated with white 
feldspar; in others, the grains are small, loosely aggregated, have a high lustre, and a red¬ 
dish yellow colour. This, together with similar grains of a beautiful red colour, belongs to 
the colophonite variety. Huge masses of a yellowish and reddish yellow colour, and which 
cleave into plates, are also abundant; and in the fissures in this variety, interesting crystal¬ 
line forms are often found. These crystals have a peculiarly resinous lustre, and a paler 
colour than is usual. The forms observed are the primary (Fig. 270); the primary with the 
edges replaced by tangent planes (Fig. 271); also the forms represented by Fig. 272, and by 
Fig. 274, in which six of the faces of the dodecahedron are so much extended as to give the 
crystal the appearance of a six-sided prism with three terminal planes; Fig. 275, in which 
two of the sides are so much enlarged as to present the form of a flattened table ; and also 
Figs. 276 and 277. 
Journal of the Academy of Natural Sciences of Philadelphia. II. 185. 
t American Journal of Science. V. 118. 
