146 
[Assembly 
tical, as we descend to the southeast, soon becomes reversed, that is, 
while its direction continues the same, its dip is to the southeast, at an 
angle varying from 45° to 90°. Here it is occasionally interstratificd 
with the argillite. As we proceed southeasterly, before we reach the 
Walkill, the argillite becomes the predominating rock. Over this space, 
viz: from Shawangunk mountain to the Walkill river, this rock, with 
the alternating argillite, extends unbroken from New- Jersey to Ulster 
county. Over the remainder of the county, until we reach the primi- 
tive region of the Highlands, it every where accompanies the argillite, 
and is interstratificd with it. It is the first rock next the primitive. It 
is found in several valleys between the western ranges of the primitive, 
and even mounts some distance up their sides, particularly the western. 
Bellvale mountain extends quite across the town of Warwick. The 
southeast side, the top, and about one-third of the descent on the 
northwest side, are composed of graywacke and graywacke slate, 
standing nearly vertical. Its colours are gray, greenish and bluish gray, 
and brick red. Many of the layers are completely chequered by veins 
of milky quartz traversing them in all directions. While it passes on 
one hand into graywacke slate, or graywacke shale, on the other it be- 
comes a perfect conglomerate. 
Skunemunk is similar to Bellvale mountain, passing unbroken nearly 
across Monroe. Its southeast side, top, and part of northwest side are 
graywacke in all the same varieties. It is not in a line with Bellvale 
mountain, neither do their lines of bearing quite coincide. Most of 
this mountain has the dip, &c. of Bellvale mountain; but High -point 
has the rock dipping to the east^ and some part of it even to the north- 
easL 
On some of the small ridges northeast of Bellvale mountain, the 
graywacke is seen forming their northwestern sides, while the opposite 
or southeast side is primitive rock. One of these may be seen a mile 
west of the Friends' meeting-house, in Monroe. In these cases the 
line of bearing and dip of the graywacke coincide with those of the 
primitive, and the graywacke has the appearance of passing beneath the 
primitive rock. At the western base of Goosepond mountain and of 
Sugar Loaf Mate, the slate has the same position in reference to the 
primitive, and exhibits precisely the same appearances. These circum- 
stances being precisely similar are mentioned together, so that future 
visiters to the neighborhood may notice both. In many places both 
rocks arc visible but a few feet apart, but I have not seen them in actual 
contact. This position of the two rocks so different in age, is singular 
