Geological and Mincralogical JVotices. 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. xvii. 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 symmeirical structures in stratified rocks ? Facts, 

 certainly, seem to lead to this conclusion. 



Boulders. — An interesting and prominent feature in the geology 

 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 io 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 roads 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 ; this proves a northerly current, of which we have 



* Since the above was written, I have received Prof. Emmons' Report on the geology of the nor- 

 thern part of New York. He finds in place rocks on a grand scale, of which the boulders here 

 cited appear to be types^ e. g. the red granite of the Kayederosseras range and at the Thousand 

 Islands, containing beds of white felspar, and especially the "gray bluish gi'een" felspathic rock 

 that contains the Labrador felspar, and whose boulders are found in the valley of the Hudson in 

 Orange Co., at Little Falls, and now at this place, and some thirty miles farther west and north. 



Vol. XXXII.— No. 2. 30 



