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The Rocks of the District. 5 
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There are low lines of cliffs all over the surface of the mountain, 
especially to the southward, but along the eastern face, where 
the grit is being continually undermined by erosion of the slate, 
they are of great prominence, in some cases having a nearly ver- 
tical height of two hundred feet and extending continuously for 
many miles. The “points” are projections or promontories of 
the eastern edge of the grit beyond the general crest line, due to 
a less degree of recession. Buntico point, Paltz point, Gertrude 
nose and Sams point are the most prominent of these, but there 
are many others of minor importance. The cliffs on the surface 
of the ranges are of various heights and lengths, and rise along 
joint cracks. ‘They face in various directions, but a north-and- 
south trend is predominant. They are usually in irregular, dis- 
continuous steps on the slopes and face each other and enclose 
depressions of various sizes on the plateaus. 
The lakes for which the mountain is famous lie in basins of 
moderate depth and are all near the top of the range. They 
are nearly surrounded by cliffs of Shawangunk grit of greater 
or less height, which add greatly to their beauty. The grit is 
mainly a messive white or gray quartzite or conglomerate, aver- 
aging 250 to 300 feet thick. The proportion of pebbles is large 
but variable, many beds being fine. The pebbles and grains are 
quartz, and the matrix is siliceous. The conglomerate is the 
famous Esopus millstone, and has been largely quarried for two 
centuries. 
The relations of the Shawangunk grit to the Hudson shale in 
the Shawangunk mountain region is one of shght but persistent 
unconformity. The coarse grit lies directly on the eroded sur- 
face of the shales. This erosion has truncated low arches of the 
slate, but has channelled its surface only shghtly. Exposures 
of the relations are everywhere abundant. One of the best in- 
stances is along the road from Minnewaska to New Paltz, two 
miles south of lake Mohonk. Here along the mountain slope a 
very low arch of the grit is seen surmounting a truncated arch 
of shales of materially steeper dip. Diversity of dip is seen at 
every locality, varying from very slight to 0°, but several points 
were observed where it was hardly perceptible. 
The corrugations in the general monocline of the mountain 
are a series of anticlinals and synclinals which traverse the range 
diagonally from north-northeast to south-southwest and begin in 
succession from northeast to southwest, their axes rising gradu- 
