274 BULLETIN OF THE 



Greenwood Lake Railroad crosses the mountain. As the valley ia in 

 line with the larger fault, they probably stand in the relation of effect 

 and cause ; the throw has very probably increased where the valley is 

 well formed. 



Sandstone was not found in the valley as far south as the Notch, 

 although the place is favorable for its preservation. If continued noi'th- 

 ward, the fault would pass east of the trap front at the Falls, and its 

 effect, if existing there in the sandstone, would be less noticeable. 



On the western foot of First Mountain two small exposures just west 

 of the Morris Canal and south of the High Bridge showed amygdaloidal 

 trap, and one of them pi'esented clear marks of variation in structure 

 bounded by curved surfaces, such as are found farther south at Felt- 

 ville. There was also seen at this point a surface much like that of 

 flowing lava or slag. 



Sandstone is not seen in the flat valley until the village of Little Falls 

 is reached, a short mile west of the First Mountain trap, where it is 

 shown in normal condition in a quarry by the canal and river, about 

 two hundred yards east of the Second Mountain trap. The right bank 

 of the Passaic here approached gives no chance of finding a junction ; 

 but on the other side, a little farther down than opposite the quarry, 

 there is a small opening in which fine trap and red sandstone both show, 

 though the contact is hidden by several feet of rubbish. The sand- 

 stone has no marks of baking. Following up stream, the trap varies 

 greatly in texture ; an irregular very amygdaloidal mass grades into 

 firm trap on one side, and into a much decomposed loose rock on the 

 other ; I have considered the latter an ash or tuff. The dense trap is 

 often distinctly columnar, and above the canal bridge it is well divided 

 by nearly horizontal open joints into sheets of varying thickness. In 

 the midst of this there is a very uneven mass of amygdaloidal trap that 

 seems to contain fragments. Farther west there is a broad area of flat 

 alluvial meadow-land. 



The trap of this region is described by Rogers (c, 146) and Cook 

 (b, 179). 



M. Feltville, J^. J. (figs. 49, 50). — Mr. I. C. Russell (a) describes an 

 upper contact in a little ravine on the back of First Mountain near this 

 deserted village ; but I failed to discover any outcrops corresponding 

 closely to his description. My time there was short, and allowed only 

 the examination of a ravine about an eighth of a mile east-northeast of 

 the village ; the stream from it enters the brook in Washington Valley 

 at the lower part of an old broken dam. Going about one hundred yards 



