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beautifully exposed on the bank of the canal for a mile above the 

 town, exhibiting the nearly parallel planes or laminae of deposition, 

 dipping with extreme uniformity to the northwest, at an angle of 

 about 15°. Some of the more argillaceous layers contain a con- 

 siderable amount of the carbonate of lime in small disseminated 

 crystals, also in the form of hollow nests, lined with crystals form- 

 ing bands of two or three inches thickness and of thin seams or 

 plates of satin spar, filling the fissures of the shale. The planes 

 of lamination are often marked by thin bands of a light bluish- 

 green calcareous shale, which owe their peculiar colour to the 

 iron so copiously present in the formation, usually as a peroxide, 

 but in these instances reduced to the condition of protoxide. 

 These bands are erroneously supposed to contain copper. 



Northwestward, as far as Boundbrook, the stratum retains 

 very nearly the aspect which it exhibits near New Brunswick. 

 The only fact of interest is the gradual declension in the angle 

 of the dip towards the northwest. Between Boundbrook and 

 Middlebrook the rocks are well exposed on the south side of the 

 river by the excavations made for the canal. Here the dip 

 exhibits an unusual direction, being towards the southeast, but at 

 an angle not exceeding 5°. This change in the inclination of the 

 strata is not merely local, but prevails over an area of several 

 miles to the northwest and west, the whole way to the vicinity 

 of Pepack in the one direction, and the junction of the north and 

 south branches of the Raritan in the other. Tracing the dip 

 along the Millstone river, in a succession of fine exposures from 

 Griggstown towards its mouth, we perceive it to be to the north- 

 west, but gradually diminishing until we approach the Raritan, 

 where it becomes horizontal, and soon after assumes the contrary 

 direction, as beheld in the vicinity of Middlebrook. The line 

 of no dip or synclinal axis is traceable continuously from Bound- 

 brook, taking a west-southwest direction through Million, or 

 Rogers' Mills, to Flaggtown. Along the southeastern base of 

 the ridge of trap, which extends from the Bridgewater Copper 

 Mine towards Pluckemin, the southeastern dip is towards the 

 hill obliquely, indicating that it is not a result of the protrusion 

 of the trap, which, throughout the region, has usually exerted 

 very little influence in disturbing the direction assumed by the 

 red sandstone formation at the time of its deposition. 



