PALEOZOIC ROCKS OF THE CANTON QUADRANGLE 1 5 



lies in the occurrence here of the " tree trunk " concretions 

 described by Hough/ Ells,^ Gushing^ and others from other regions. 



A mile east of the last, well drillers on the Henry Douglas farm 

 just northeast of Crary's Mills (88) struck sandstone of rather 

 light color about 45 feet below the surface, and penetrated it for 

 some distance. Though the extent of this area is unknown, the 

 find emphasizes the fact that Potsdam strata are likely tO' be 

 encountered anywhere in the drift-mantled places and that their 

 actual distribution may be much more general than has been sup- 

 posed. More surprising proof of this was afforded by the well at 

 Frank J. Crary's (locality 84') one and one-half miles west of 

 Pierrepont, where the drill passing through 28 feet of till found 

 about 130 feet of typical red Potsdam sandstone, at the bottom of 

 which it dropped into a water pocket believed to mark the basal 

 contact. In the brook channel three-fourths of a mile west, below 

 the falls (600 foot contour), there are hematite- charged schists 

 indicating that the Potsdam has been but recently removed, while 

 one and one-fourth miles northward (84) in the brook bed north 

 of the brick schoolhouse is a close pavement of red, purple and 

 saffron sandstone blocks that have been quarried for foundation 

 stones. All these circumstances point to a large area of sandstone 

 underlying this big morainal hill. 



The most interesting Potsdam locality of all is the out-of-the- 

 way one at Mr Dillabaugh's (85) in the southeast corner of the 

 quadrangle (plate i). Here stowed away under Benway hill at 

 an elevation of over 800 feet is a little ledge and glaciated knoll 

 (figure A) on the east side of the road and a quantity of loose 

 masses (figure B) on the other side, of the ferruginous basal Pots- 

 dam breccia, whose cavities contain elegant crystallizations of 

 hematite and quartz. The rock is highly indurated, hardly clastic 

 in appearance, and but little of the ordinary sandstone is seen. 

 Beneath are Grenville limestones, while behind are nearly vertical 

 cliffs of gneiss embracing and sheltering the ledge within the sig- 

 moidal curve described by Doctor Martin.^ Two miles southwest 

 (86) in the same valley of Van Rensselaer creek large loose blocks 

 of somewhat similar stuff (plate 2) are piled thickly for many 



13d Ann. Rep't, N. Y. State Mus. (1850), p. 32-33, figure; and Proc. Am. 

 Assn. for Adv. of Sci., 4 (1851), p. 352-54. 



^ Roy. Soc. of Can. Trans., ser. 2, 9 (no. 4), p. 103. Geol. Sur. of Can. 

 Ann. Rep't for 1901, I4:I76A (1905). 



^ N. Y. State Mus. Bui. 145, p. 61, pi. 13. 



*N. Y. State Mus. Bui. 185, p. 96. 



