CHAMPLAIN DIVISION. 
387 
recently been uncovered of the overlying clay, by exca.vating roads, or the action of water. 
One locality was observed about two miles south of Redhook landing, where two distinct sets 
of scratches were engraved on the rock, with directions of S. 10° W. and S, '20° W.* * 
The smoothed or scratched grit or greywaclie was seen -between Rhine!)eck landing and 
village, west of the ridge of naked grit rock that paves the road west of the creek; also at 
several places on the Rhinebeck and Pineplains turnpike road; also two and three-quarter 
miles from Lower Redhook village on the road to Long pond. 
A quarry of flagging stone, and for building stone, has been opened near Lower Redhook 
village (about half a mile east), in the slaty grits of the Hudson-river group. The stone is 
easily quarried in slabs of five to fifty.square feet, and three to eight inches,thick. 
A broken rocky ridge of grit and slaty grit interstratified witfr^slate, extends from near 
Rhinebeck, by Hydepark, to ne^Poughkeepsie. It is on the eas’t'^of the old post-road, but 
the strata are exposed in many places aldn'g' the roa^r The dip of the rocks is eastwardly, 
generally east-southeast, at very variable angles from forty to ninety degrees. At Lewisville 
opposite Lewis’s landing, the stmta are vertical. ■ „ ' 
The smoothed and scratched^eywac]^ or grit was obs^ved on the ridge east of Hyde¬ 
park ; and about half a mile ea,st of the p“3st-road opposite to half a mile north of De Graff’s 
tavern, the grooves and scr^ches, which were perfectly similar in size, depth and direction, 
were interrupted by slip|'or^liglwLaults of the rock since the scratches have been made. Prof. 
Cassels observed them in several places in that vicinity.' -" .The edges of the rock, both above 
and below, on the slip, were" sharp, ^nd the grooves .andTcratches of the lower mass were con¬ 
tinuous plump up to the surface' of ' the upper mass ; and on the upper, mass they were con¬ 
tinued quite to the sharp edge a^g which the slip has taken place. Similar facts have already 
been stated in the article on the ®ift deppsftsj^ occurring'in slate between Qopake and Boston 
corners, and in several localiti^about one mile west^of Long pond in Clinton^'Dutchess county. 
Flagging stones are quarried.from the^^aty grits) about a mile east of the red^school-house 
in Hydepark. . 
The rocks are well exposed||)etween Hydepark village and landing, and along the shore 
from the landing some distance to th^north. The grit, com^sed of distinct particles of slate 
in addition to the usual materials^is interstratified with a fissile slate, almost like roofing slate, 
a little above the landing on the shore. The rocks are dlso traversed by numerous veins of 
calcareous spar, and by some of quartC The long narrow island and several smaller ones 
between Hydepark and Lewis’s landing, offer fine, exposures of the grits and slaty grits of 
the Hudson-river group. ■ ’ - 
We will now trace the shore from Hudson to Barnegate and Fishkill. Rogers’s island is 
situated between Hudson and Catskill. Mosrbf it is alluvial, and frequently overflowed by 
the tides; but the southwest part of the island is composed of rocks of the Hudson-river 
group, rising ten to forty feet above the tide level. 
* They have'been more particularly described under the head of Drift deposits, Diluvial scratches or Drift scratches. 
• 49* 
