106 BULLETIN OF THE 



well known in the neighborhood and easily reached by a walk of two 

 miles and a half from Cheshire station of the New Haven and North- 

 ampton Railroad, or by a less distance from the station of the same 

 name on the Meriden, Waterbury, and Connecticut River Railroad. It 

 gives the only good exposure of the overlying strata known to us on the 

 back of the western trap sheet, and deserves careful examination. 



The trap here is without vesicles throughout its mass; holocrystal- 

 line except at contact with other rocks ; at itL' upper contact it is 

 extremely fine-grained and glassy ; flowage action is seen in the micro- 

 scopic arrangement of the feldspar prisms parallel to upper line of 

 junction. U])per surface of sheet obliquely traverses the beds of the 

 overlying sandstones and shales ; several small offshoots of fine texture 

 extend into the overlying rock (Fig. 12). Pebbly sandstone directly 

 above the sheet does not contain fragments of trap, and is not per- 

 ceptibly affected by the igneous mass even close to the junction ; the 

 shales that elsewhere approach the sheet are apparently indurated. 

 See special account. 



Section numbers, 45-55. Palisade Range, New Jersey. 



The easternmost or lowest trap sheet of the New Jersey Triassic area 

 seems to correspond with the lowest or westernmost sheet of the Con- 

 necticut area, and is therefore referred to here in order to extend the 

 number of examples quoted. Its base is finely exposed in contact with 

 the underlying sandstones at the Hamilton-Burr duel ground in "Wee- 

 hawken, on the bank of the Hudson, opposite New York City ; this out- 

 crop is well figured in Plate IV. of the Annual Report of the New Jer- 

 sey Geological Survey for 1882. Other exposures of the xmderlying 

 sandstone are common up the west bank of the Hudson, but contacts 

 are relatively rare. The only upper contact known is one pointed out 

 some years ago. by Professor Cook (Geology of New Jersey, 1868, p. 201), 

 in Englewood, about a mile south of the station of that name on the 

 Northern New Jersey Railroad, in a brook channel a few hundred feet 

 west of a road. 



The trap of this sheet is dense throughout, as far as examined at 

 numerous outcrops. Its texture is rather coarse in the middle of the 

 sheet, but becomes very fine at lower and upper contacts. The adja- 

 cent bedded rocks are distinctly altered from their original condition, 

 with the development of new minerals. No fragm'ents of trap are 

 found in the overlying beds. 



Under the microscope the trap is seen to be almost identical with that 



