CORUNDUM IN IGNEOUS ROCKS. 39 
A band of amphibolite that is conformable throughout its entire 
extent with the sericitic schists of this section of the State extends 
ahnost continuously across the State, north and south of Chester. 
The strike of this band of aniphibolite is dei)endent upon the wind- 
ings of the schists, and its dip is approximately 1)0". Its width wdll 
average only a few rods, but in the Aicinity of Chester, a few miles 
both north and south of the town, it is t]iree-(|uarters of a mile wide, 
and it is in connection with this broad band that the emery is found. 
The emery occurs on the eastern side of the ami)hibolite, and is sep- 
arated from the sericitic schists by a narrow band of aniphibolite, 
which varies in wddth from an inch or two to nearly 18 feet. Some- 
times there has been considerable serpentinization of the aniphibolite, 
and the emery is separated from the schists by serpentine. Across 
the AA'estfield River from the point wdiere the emery is first encoun- 
tei-ed the aniphibolite is rei)laced by serpentine, and it is in this be([ 
of serixmtine that crystals of emery, pseudomorphous after olivine, 
are said to occur, specimens of them being in the geological collection 
at Amherst College. 
The aniphibolite is in api:)earance a finely laminated roclv made up 
of interruj^ted thin sheets of feldspar grains and of jet-l)lack needles 
of hornblende, and usually contains more or less green epidote. 
The sericitic schists on the w^est of the aniphibolite, which are 
described by Professor Emerson under the head of tlie '' Rowe 
schist,'' " are biotitic and feldspathic, and often contain garnets that 
are more or less altered to chlorite. The schists on the east are 
described as the " Savoy schist," ^' and are chloritic sericite-schists, 
mostly of a light-gray color, witli a sliade of giHH'ii, due to tlie chlorite 
that is mixed with the muscovite. AYhen the chlorite can not be 
seen with the eye, it is readily detected under the microscope. In 
some places the proportion of chlorite has increased until there are 
considerable aggregations of this mineral along the planes of lamina- 
tion. Garnet and pyrite are also abundant in certain portions of the 
schist. 
The emery vein can l)e foUow^ed for a distance of nearly H miles, 
starting from a point at the north end of the broad band of am[)hib- 
olite, on the left bank of the ^Vestfield River, just above the railroad 
bridge of the Boston and Albany Railroad. The general strike of 
the vein is a little east of sonth and runs for the most part parallel 
to the line of contact of the aniphibolite and schist. Kmery is not 
found throughout the vein, but the vein cnn be traced almost con- 
tinuonsly by means of streaks of chlorite. The vein varies in width 
"Mon. TT. S. (Jeol. Survey, vol. 2i), 1898, p. 76. 
Mbid., I). 15(5. 
