THE 
AMERICAN GEOLOGIST. 
Vol. XXX. AUGUST, 1902. No. 2. 
TWO CASES OF METAMORPHOSIS WITHOUT 
CRUSHING 
B. K. Emeksox, Amherst, Mass. 
PLATE I. 
I. Ax AMYGDALOIDAL AMPHYBOLYTE FROM THE CONNECTICUT 
VALLEY 
It is Still a very difficult matter to distinguish amphibolvtes 
d(-rived from basic eruptive rocks from those derived from 
Cc'Icareous and ferruginous sedimentary rocks. I was there- 
fore much interested in a pebble of a black amygdaloidal am- 
pliibolyte which was recently brought to me from ]Mt. Hol- 
ycke. It seems to have come from the large bed of magnetite- 
amphibolyte in W'hately,* a slide of which is figured on piate 
\l, fig. I. of the "Monograph of the Three River counties" 
and classed there with the amphibolytes probably derived! 
from limestone. This specimen, as shown in figure i. is cer- 
tainly an amygdaloid and the shapes of the rounded white 
spots are unmistakably those of steam holes. The lower fig- 
ure is a photograph of natural size of a polished surface cut 
through the middle of the pebble. The upper figure is the 
photograph of a slide cut i mm. above the lower one. 
The mass of the rock is however now a dark green and fine 
grained amphibolyte and is wholly changed from its original 
condition into a matted mass of fine actinolite needles, some 
almost colorless and showing only low pleochroism. A few 
of them larger than the rest project freely into the cavities 
v;ith perfect terminations, and the ends are often colorless. 
*Thts is 15 miles up the Connecticut valley, in the direction from which the 
ice came. 
tMon. XXIX. U. S. Geol. Survey, 1898. 
