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tion, and caused it to dip to the south and southeast. This 

 disturbance of position does not, however, prevail over perhaps 

 more than half a mile ; and it is singular enough, that adjacent 

 to and between the three other bold ridges of trap which cross 

 the strata nearer Trenton, no similar displacement of the prevail- 

 ing dip has taken place. I may mention in this place, the same 

 interesting fact in connection with nearly all the principal out- 

 bursts of trap rock in the State, which produce no disorder in the 

 original attitude of the strata, though conclusive evidence will be 

 offered presently, that the trap must have issued through the stra- 

 tified rocks after their deposition. The stratified sandstone rises 

 almost to the top of Goat Hill on its eastern slope, dark and altered 

 in texture, but preserving its ordinary dip to the northwest. 



Upon the northwest side of the large ridge of trap called Goat 

 Hill, there have arisen changes in the mineral contents and struc- 

 ture of the adjacent strata which are highly curious and impor- 

 tant when regarded in a scientific point of view. I allude to the 

 existence in the sandstone of a profusion of nodules and crystals 

 of epidote, tourmaline, and other minerals hardly ever found but 

 in igneous and volcanic rocks, but caused here by the heating 

 influence of the vast mass of trap, as it issued from the interior, 

 in a molten state. When treating of the trap rocks of the red 

 sandstone region generally, I shall dwell more at length upon 

 these interesting mineralogical changes. 



This broad tract of argillaceous red sandstone and shale is in- 

 tersected in its range to the northeast by the valley of the Rari- 

 tan, where its beds are finely exposed to observation the whole 

 distance from Perth Amboy to Boundbrook. To the north- 

 east of the Raritan, nearly the whole of that part of the middle 

 secondary region included between Staten Island and the Hudson 

 on the east and the trap ridges on the west, consists of this divi- 

 sion of the formation. Resting upon this rather uniform portion 

 of the series, we find near the Delaware another somewhat more 

 varied set of strata extending between the small stream below 

 Centrebridge and the Wickhecheoke, about two miles above its 

 mouth. They consist of a series of alternating red sandstones 

 and coarse yellowish conglomerates, occasionally divided by 

 narrow beds of the softer argillaceous red shale. These conglo- 

 merates resemble closely those which occupy an inferior position 



