of the Eastern States. 223 



The Red Shales and Sandstones. 



The sandstone, so extensively developed in this formation, 

 is well known to the citizens of New York and the neighbor- 

 ing cities as " brown stone," of which so many of both their 

 public and private edifices are constructed. This reddish or 

 brown sandstone almost invariably occurs interbedded with 

 layers of soft crumbling shale. These are but varying deposits 

 from the same waters,'which at one time were charged with mud 

 and deposited shale, and at another time spread out a layer of 

 sand, which at length became consolidated into sandstone. 



We can only notice at present a few of the localities where 

 these shales and sandstones are unusually well exposed, re- 

 ferring our readers for greater detail to Prof. Cook's Geology 

 of New Jersey, and to H. D. Rogers's reports on the geology 

 of the same State. The first locality we will notice is on the 

 line of the Montclair Midland Railroad, about four miles 

 westward of Jersey City, and near the village of Arlington. 

 Here the sandstone forms a line of bluffs, which border the 

 Newark meadows on the west, and were doubtless at one 

 time the shore-line. In these bluffs, a deep cut, made for the 

 passage of the railroad, exhibits on its side an interesting sec- 

 tion of the alternating layers of sandstone and shale, which, at 

 this point, have an inclination of about fifteen degrees towards 

 the northwest. As this excavation is more than a quarter of 

 a mile in length, and has been cut down to a depth of 60 

 or 70 feet from the surface, it affords as fine a section of the 

 Triassic rocks as is known to us.* 



*Perhaps the most interesting feature in this section is the occurrence near 

 the middle of the cut, of a great fissure which has parted the rocks in a nearly- 

 north and south direction, or parallel to their strike. This fissure is about 

 five feet wide, and is filled in with debris from the red sandstone rocks ; 

 its walls are altered as if by the action of heat, and when broken are of a 

 bright brick-red color. The fragments filling the fissure are small near the 

 walls and imbedded in an earthy or shaly mass. They are nearly rounded, 

 and show polished or " slickenside " surfaces. The centre of the fissure is 

 filled with large angular masses of sandstone, which show more alteration 

 both in texture and color than the walls, and also show slickenside surfaces . 



