Prof. G. H. Stone—Stones of the Salt Range. 417 
of the stone the fresh surface was seen to be of a lighter and more 
rosy colour than the original surface. The felspar grains and crystals 
of the surface are perceptibly roughened. The stone is thus proved 
to be weathered, though the discoloured layer is quite thin. The 
composition and structure of the porphyry indicate that it is a very 
enduring rock. The striated surfaces, even at the bottom of the 
broader scratches, are apparently as much weathered as the rest of 
the stone. There are four principal planed facets, and their sides 
are nearly parallel like those of the faces of a prism. One face is 
nearly plane, the others have a curved or broken-curved cross- 
section. The facets have been reduced to an even surface and afford 
a marked contrast to the rough fracture surfaces. The scratches are 
quite straight and distinct, though their sides are not so sharply 
defined as is usual on recently facetted stones. The whole outer 
surface has received a fine polish, such that the apices of the larger 
projections have been rounded and the smaller ones nearly erased. 
The stone is three inches and three-quarters in length, and its greatest 
transverse diameter is two inches and three-quarters. The angles 
between the facets are not sharp, partly in consequence of the fine 
polish before described, and partly because the planed surfaces do 
not in general meet, but are separated by a narrow strip of unplaned 
surface retaining the uneven form due to fracture, except as it has 
been modified by the fine polish before mentioned. 
No. 4. Sent to me direct from India by courtesy of a returning 
missionary. Diameters, two inches and an eighth to three inches 
and a half. It is composed of a light red porphyry. Most of the 
larger grains and imperfect crystals of felspar which are exposed 
on the planed facets have weathered so as to be quite rough. There 
are a number of small irregular depressions on the planed faces 
caused by the partial weathering of the less resistant grains. The 
smooth facets are arranged about an axis roughly after the manner 
of the faces of a prism, and one end of the imperfect prism thus 
formed is also planed. The remainder of the surface is uneven, 
and is simply a fracture-surface modified by a fine polish, which has 
removed the apices of the angles and the smallest of the projecting 
points. Some of the faces do not show distinct scratches, though 
planed to a flat and even surface. The surface of this specimen has 
been more modified by weathering than No. 8. The weathering 
involves the bottom of the scratches as well as the unscratched 
surfaces, and there is little, if any, difference in the depth of the 
weathering in different parts of the stone. 
No. 5. Also sent direct from India. It is about three inches long. 
It is a fragment recently broken off from a water-rounded cobble 
that was probably about six inches in diameter. It is composed of 
compact, fine-grained quartzite, which here and there contains 
microscopic grains of felspar. One portion of the cobble has been 
distinctly planed and scratched. At least one quarter of an inch has 
been ground away from the stone, if we estimate its original shape 
from the curves of the rounded portion of the stone adjacent to the 
planed facet. The scratched surface presents gentle undulations 
DECADE III.—VOL. VI.—NO. IX. 27 
