Geological and Mineralogical Notices. 233 
quity of the rock,” and “ was well exemplified in the older slates 
and limestones,” receives marked confirmation from this instance, as 
well as from the rhomboidal sandstone near Hartford, (Vol. xvsr. p. 
124.) Is there in these examples (the sandstone is without doubt 
calcareous) the result of an unknown or the modification of a known 
law analogous to crystallization? Is not the rhomboidal the more 
common of all symmetrical structures in stratified rocks? Facts, 
certainly, seem to lead to this conclusion. 
Boulders.—An interesting and prominent feature in the 
of this region, and which cannot fail to attract the notice of every 
casual observer, is the numerous and immense boulders of primitive 
rocks, unlike any thing he would find here in place, which are scat- 
tered every where over the surface. They are principally of the 
granitic family—a red sienite prevails—masses of decidedly horn- 
blende rocks—others composed entirely of white feldspar and glassy 
quartz—others still of grayish feldspar with brilliant cleavage-surfa- 
ces and crystals of mica and scales of plumbago.* One single boul- 
der was discovered very much resembling the Labrador felspar— 
contained no quartz—but many small four sided prisms not unlike in 
external appearance to zircons. ‘These are scattered upon the hills, 
accumulated in the valleys and the beds of streams, particularly of 
Black river, running north, and of Lansing’s Kill, a branch of the 
Mohawk, running south. Boonville is the summit level of this region, 
being about six hundred feet higher than the level of the Erie Canal 
at Rome, and its waters part, descending north and south. The gravel 
hills cut through by the voads show the boulders buried throughout, 
twelve or fifteen feet from the surface. These and others found in the 
streams, as at the accumulations below High falls in Black river, bear 
the marks of long continued attrition, and are smoothed and rounded, 
while the larger ones on the surface, which from their size appear 
almost immovable, would seem from the freshness of their fracture and 
their salient angles, to have been simultaneously and by the same cau- 
ses, separated from their original bed and transferred to their present 
position. ‘The source of these rocks must be sought in the north and 
east, as none of their character exist probably south of this place in 
the whole state ; nas — a a current, of which we have 
* Since ived Prof. Emmons’ Report on the geology of the nor- 
tot New ew York. © "fs pace sar Soak anid of here 
cited sappett to be types, e.g. the red granite of the Kayeder ‘as range and at the Thousand 
islands, 
ing beds of white aren and especially the “ deg “binish sini ae rock 
that = Labrador ot e boulders are found in the valley of the Hudson in 
Orange Co., at Little Falls, and n is place, and some thirty miles farther Nae and north. 
so ts XXXII. pile. 2 2. 30. 
