RELATION OF VEINS AND NODULES. 165 
inite arrangement, in one or two places they were found arranged in 
rows. The nodules in such rows vary somewhat in diameter, though not 
greatly, and are at first separated by an interval of two or three inches. 
On following along the line, however, they are found to come closer to- 
gether and then to form a continuous string, touching one another, the 
long row of contiguous balls being here and there interrupted by spaces 
of the normal granite. Still further on, as indicated in figure 1, the 
EROS 6 0ClO C00 6 CO ee 
FicureE 1.— Vein passing into separate Nodules. 
One-fiftieth natural size. 
nodules of the row are found to fuse or coalesce, at first into a series of 
sausage-like masses and then into a continuous band, having the width 
of a single nodule, a band which as exposed on the glaciated surface of 
the rock no observer would hesitate to regard as a true vein filling a 
fissure, could not its passage into the separate nodules be distinctly traced 
(see plate 11, figures 1,2, and 3). ‘These “veins,” moreover, in some cases 
show a rude banding parallel to the walls, for the concentric structure 
of the nodules passes naturally over into the banded structure of the 
vein. The quartz which is more abundant in the outer portion of the 
nodules is thus more abundant on the sides of the vein, while muscovite 
and feldspar, being more abundant toward the center of the nodules, are 
also more abundant toward the middle of the vein. The relation of the 
“vein” to the series of spherical masses, moreover, is indicated by the 
successive little sponge-like bunches of tourmaline rounded in general 
outline, like those found toward the central part of the nodules, which 
are distributed along the length of the vein at more or less regular inter- 
vals (see figure 2). In some cases even traces of the medial line can be 
seen on the weathered surface, 
en Saye aren passing down the length of the 
a oe co = 3e ES vein and suggesting the meet- 
ing place of the combs in the 
combed vein (sce plate 11, fig- 
urel). These “veins” are well 
defined against the granite, al- 
though the boundary is not absolutely sharp, and occasionally they split 
and fork as other veins do, and pass into a row of nodules (see plate 11, 
ficure 3). Their continuity in depth could not be so well studied, as 
they are exposed chiefly on horizontal surfaces. In one instance, how- 
ever, on the face of a little cliff, one of them could be seen to extend 
vertically through the granite in a direction at right angles to its strike 
for a distance of three feet and then downward out of sight. Itis certain 
Figure 2.—Sponge-like Bunches of Tourmaline. 
Arranged at intervals along a vein, One-fifth nat- 
ural size. 
