MUSEUM OF COMPARATIVE ZOOLOGY. 327 



knob of rock alongside of the Mountain road in the village of Catskill 

 just west of the stream ; its steep northern slope gives a good small 

 example of an overhanging polished surface. The only case of glacial 

 action noted on the limestones was on the western side of the Cornifer- 

 ous anticlinal, where the Kaaterskill has recently cut away the pro- 

 tecting clays, just south of its cross valley by the saw-mill : these stria) 

 are very well preserved ; they run horizontally along the steep lime- 

 stone stratum, parallel to the valley. The Hamilton and Catskill sand- 

 stones west of our limestone belt preserve many and distinct scratched 

 surfaces : the largest of these was found on a bare even bed of rock on 

 the Mountain road at a four-corners, about half-way from the Marcellus 

 valley to the foot of the long grade ; they bear S. 20° W., and some 

 are continuous for fifty feet. A little farther west the same direction 

 is repeated, and with it there are many straggling scratclies turning to 

 S. 60° W. On the mountain road ascending to Beach's Mountain 

 House, about half-way up its long grade, the scratches run S. 25° W., 

 parallel to the mountain foce. On the new road leading from the 

 Kaaterskill Hotel eastward across the plateau to South Mountain, the 

 freshly uncovered sandstone ledges show very distinct Stossseilen, indi- 

 cating an ice-overflow from the Hudson valley across the mountain and 

 up the Palenville clove ; the directions of ice-motion, here clearly deter- 

 mined by the form of rock-surface and the well preserved scratches, 

 were N. 80°, 75°, 50°, and even only 35° "W., giving a westward deflec- 

 tion from the main valley of more than a quadrant.* 



The general absence of drift over the limestone belt and the sand- 

 stones to the foot of the Catskills is noteworthy ; largely on this absence 

 depends the clearness of the topography of the region. There are no 

 sheets or mounds of till or gravel ; everywhere but in the deeper valleys 

 the country rock comes close to the surface and appears in abundant 

 outcrops ; And the drift is recognized only in scattered stones and boul- 

 ders of northern origin : in French's quarry there is, for example, a two- 

 foot boulder of garnetiferous granite, presumably from the Adirondacks. 



There is no clear evidence of any marked effect of glacial action on 

 the topography, unless we place the little Black, Canoe, and Van Luven's 

 lakes here ; but they are small, and probably very shallow, and quite 

 as likely the result of drift obstruction as of ice excavation : they all 

 occur on the lower part of the grits, where these join the Upper Pentam- 



* This deflection has been observed by Mather, 1843, 203 ; Runisay, Quart. 

 Joum. Geol. Soc, XV., 1859, 208 ; and Julien, N. Y. Acad. Sci. Trans., 1881. 

 24-27. 



