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Rte eee 
Geology, &c. of the Connecticut. 29 
ers. I shall confine my remarks principally to that range 
extending from — to Northampton, because I have 
examined this m 
s above is doa this range appears to be most] a si- 
enitic granite, that is, a modification of granite; and very 
different from that sienite which is associated with gray- 
wacke and greenstone. A person coming from the wesi or 
north-west towards the village of Northampton, will pass 
over the most decided granite, associated with mica slate, 
till he comes within four or five miles of that place. He 
will then find the texture of the rock to be finer, and in some 
instances it contains a portion of hornblende, while the pro- 
portion of quartz is somewhat. diminished, the felspar 
frequently becomes red. Veins of graphic and common 
granite, iti » Xe. are more Preset and the rock ap- 
yect, while in a “or nah few 
feet distant, this mineral is Pabelly wanting. ccd 
er N orthampton, however, we find the hornblende more 
and more abundant, until we arrive at the eastern edge of 
the range, where we finda rock containing little else than fel- 
spar and hornblende,forming a real sienite. [have never yet 
seen a specimen, however, in which careful inspection could 
not discover both mica and quartz. ‘The felspar is usually 
deep flesh colored, and the hornblende sometimes black 
and sometimes green. On the eastern border of this range, 
especially about two miles north of the village of Northamp- 
ton, on the west side of the stage road, this sienite assumes 
a trappose and somewhat columnar fortn, both among the 
loose masses and those in place.* Among the debris, the 
three sided pyramidal form is most frequent; sometimes we 
find a three sided prism, and sometimes, both among the 
loose masses and those in place, two, three or four faces ofa 
prism of a greater number of sides. 
Another spot for observing some interesting facts in re- 
gard to this rock, is the south part of Whately. Two miles 
south of the congregational meeting-house, on the road to 
*This fact was first mentioned to me by that indefatigable and able natu- 
ralist, Mr. Thomas Nuttall. 
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