of the Eastern States. 237 



in this case — are parted by seams of incoherent sand and shale. 

 Beyond this, and abutting against the hornblende gneiss which 

 composes the foot-hills of the Highlands, the conglomerate be- 

 comes more compact, with less shale and larger fragments of 

 included rock. In every respect, even to minute details, this 

 exposure exhibits the features which 1 had previously decided 

 should occur when a stream like the Minnescongo Creek flows 

 down from the highlands and enters the sandstone country. 

 [See note B, page 254 ] 



It may be gathered from the above that I look upon this 

 variegated conglomerate as. emphatically a shore deposit. It" it 

 is desired to trace the boundaries of the Triassic estuary in 

 which these red shales and sandstones accumulated, it is evi- 

 dent that it can be done by noting the position of the coarse de- 

 posits that formed along its shores. The western shore-line is 

 thus clearly defined, from Stony Point on the Hudson, all the 

 way to the Potomac, and far into Virginia. In fact, a glance 

 at the bold line of bluffs, composed of crystalline rocks, which 

 rises to the westward of this belt of conglomerate, and stretches 

 away in a series of blue receding headlands, leaves but little 

 doubt that this was the ancient shore against which the waves 

 broke and retreated millions of years ago. 



When we go eastward in quest of the band of coarse shore 

 deposits which should mark the eastern outline of the Triassic 

 estuary, we can find no indications of such a deposit in New 

 Jersey. All along the bank of the Hudson, from New York 

 Bay to Stony Point, — the eastern boundary of the present area 

 of this formation — the sedimentary strata are exposed in vari- 

 ous places beneath the trap rocks of the Palisades, but always, 

 with one exception, presenting their appearance of red shales 

 and sandstones. This one- exception is opposite New York 

 city, under the heights of Weehawken, where the trap rests 

 upon a coarse arkose, which sometimes contains pebbles an 

 jnch or more in diameter, together with angular fragments of 

 felspar. This deposit, however, is of limited extent, and does 

 not resemble the formation of which we are in search. 



If we go farther eastward and cross the crystalline rocks 



