344 J. D. Dana—Helderberg rocks in the Connecticut Valley. 
nated parallel with the bedding. Whether this is so or not 
with the roofing slate of the region is not positively known; 
the probability is against it. 
The limestone is crystalline, some of it coarsely so, and much 
of it impure. It contains in places disseminated pyrites, and 
large portions have consequently rotted away, and left beds of 
limonite. The purer kinds, on the surface of fresh fractures, 
are generally coarsely crystalline, and have nothing clearly in- 
dicating the presence of fossils; while a weathered surface of 
the same block may be covered with prominent crinoidal stems. 
The sight of a locality of Crinoids in the heart of metamor- 
phic New England is calculated to impress the mind strongly 
with the belief that it isa key that will open the mysteries of 
New England geology. The Geological Report of Vermont 
states that a quartzite formation occurs in the next town to the 
north, Vernon, the southeast town of Vermont, and the Massa- 
chusetts Report, that it is also largely developed just across 
the Connecticut River, in the town of Northfield ; and this sug- 
gested the true way of bringing the key into use. : 
After a first visit to the village of South Vernon—six miles 
northeast of Bernardston—with this object in view, I visited 
the region again in 1871, by appointment with Prof. CO. H. 
Hitchcock, then, as now, State geologist of New Hampshire. 
The quartzite of South Vernon was found to be overlaid by an 
an outcrop of quartzite giving positive evidence of the gt 
oy of the two. The strike of the beds at this place 
syenitic 
gneiss containing the hornblende partly in oblong pointed orys 
tals, and staurolitic slate; but we failed to find any apes 
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