388 The American Geologist. December, 1903. 
it is not essentially different from the foregoing. Hornblende in 
this rock is. however, not mentioned. 
Another quartz dioryte gneiss (1275) ' s distinctly foliated 
and contains, with the minerals of the last, also hornblende, 
more orthoclase and some sphene. Its structure is granular. 
The altered limestones "constitute the dark basic rocks 
interbanded with the limestones near the granite contact.'' They 
aia- pyroxene gneiss or amphibolytes according to the presence 
of pyroxene or of hornblende. A pyroxenyte 1 [269) is very 
fine-grained, friable, greenish-gray, and distinctly banded, being 
made up of dark-colored bands alternating with bands of 
medium and light color. The dark bands are composed almost 
exclusively of plagioclase, hornblende and augite. The lighter 
ones are intergraded amongst themselves, by reason of banded 
variations in the relative proportions of the constituent minerals. 
These minerals are combined as plagioclase, scapolite, augite : 
plagioclase, microcline, calcite, augite ; plagioclase, calcite/ au- 
gite. with subordinate amounts of quartz, sphene, apatite, horn- 
blende, ilmenite, epidote and biotite. The structure is gran- 
ulitic, with mosaic appearance. 
A scapolite amphibolyte ( 1272) is fine-grained, somewhat 
friable, greenish-gray, foliated and banded in darker and lighter 
bands. The darker bands consist essentially of hornblende with 
scapolite, and the lighter of the same with more scapolite,' while 
as accessories are calcite, pyroxene, labradorite, quartz and 
sphene. Structure is granulitic with a mosaic of polygonal 
grains. 
An amphibolyte (1270) consists of hornblende and labra- 
dorite, essentially, with small amounts of quartz, scapolite, cal- 
cite, orthoclase and augite, and still smaller amounts of sphene, 
titanic iron ore and apatite. The structure is granulo-granu- 
litic. "but still points to recrystallization of the component min- 
erals." 
The dark masses included in the granite are often near 
areas of gray gneiss. They grade in "form, appearance and. 
composition, from angular, black and exceedingly basic near 
the contact to lenticular masses with alternately light and dark 
.bands, and less basic farther away in the granite mass." An 
amphibolyte ( 1267 A. B. C.) of this source consists microscop- 
ically largely of hornblende with a considerable amount of 
