272 BULLETIN OF THE 



in which no rock is now to be seen, and it is not fully proven not to be 

 a fault like that at Garret liock, Paterson. There is a longitudinal 

 valley on top of the Palisade Range at Fort Lee, but coarse trap is seen 

 so plentifully on its two slopes that there is little room for sandstone at 

 the bottom ; and its cause is very probably a fault. Cook also notes 

 that the trap of the Palisades is remarkably uniform and very hard 

 (6, 178). 



L. Paterson and Little Falls, N. J. (figs. 47, 48). — First and Second 

 Mountains* are here cut through by the Passaic. The flat country 

 back of the broad gap and the considerable quantity of drift in tlie 

 neighborhood indicate that the present course of the river is not its 

 course during preglacial times of greater land elevation. We cannot, 

 therefore, now see the old valley bottoms, so that hei'e, as on most of 

 the Palisade Range, the back of the trap is stripped of its sandstone 

 cover below the present general surface of the valley drift, and upper 

 contacts cannot be found. In spite of the deep river gorges, and the 

 large areas of trap exposure, I was unable, in searching a day and a half 

 in this district, to find any sandstone lying on the trap ; but lower con- 

 tacts are seen at several points. The best of these is in the gorge below 

 the Passaic Falls at Paterson : on the left bank the exposure is in a 

 high bluff, not easily reached ; on the right the trap is quarried for pav- 

 ing-blocks, and a fresh contact constantly shown and easily accessible 

 (fig. 48). 



There are red strata of firm sandstone and thin-bedded shale cut 

 below the trap, and up to a few feet of the junction they show no marks 

 of alteration ; both can be matched closely at many points distant from 

 any igneous rock. Within a foot of the contact the sandstone becomes 

 firmer than usual, and shows rusty cavities, presumably a metamorphic 

 effect, as they are most numerous by the trap. The upper half-inch of 

 sandstone is darker than the rest but still reddish. The line of junction 

 is easily found and traced ; it is parallel to the sandstone layers, and 

 nowhere cuts across them ; the slight waving irregularity that it shows 

 does not demand intrusion for its explanation. Specimens are easily 

 broken out showing the two rocks welded together. The mass of the 

 trap in the gorge is dark, fine, and even in texture ; farther back from 

 the sandstone it becomes coarser, but no samples were found so coarse 

 as those from the Jersey City cut or from Goat Hill on the Delaware. 

 Close to the junction, amygdaloidal cavities are very plenty ; but most 

 of them are within a foot or even half a foot of it, and here the trap is 

 * Called the "Watchung Mountains iu Cook's later Eeports. 



