322 ■ C. N. FENNER 



Going southward from this point along the mountain road there 

 are positive evidences at many places, as indicated on the map. I 

 have no doubt that with some search other characteristic exposures 

 can be found in this vicinity. 



Southwest of the mountain reservoir there is another large area 

 shown. Along the road and in adjacent fields the trap is very vesicu- 

 lar. Plowed fields are filled with the honeycombed fragments and 

 some is plainly in place. A little to the westward the stone walls are 

 built of the crusted bowlders and rock of this structure is also found 

 in place. 



South of Great Notch the occurrences in the pipe-line tunnel and 

 in the old quarry of Francisco Brothers have been described. Fran- 

 cisco's new quarry also shows it well at the southern end. 



About a half-mile south of Great Notch station is the reservoir of 

 the Newark water department. The work here was done in 1902 

 and at that time the progress of the work showed the character of the 

 trap underlying the valley. From the gate-house a deep trench was 

 excavated North and South as a foundation for the dam. In this the 

 trap was very porous and vesicular for many hundred feet. From 

 the surface to a depth of twenty feet or so the trench showed bowlder- 

 drift. For probably forty feet below this the trench was in rock, very 

 vesicular, with abundant minerals. Stilbite, chabazite, heulandite, 

 prehnite, calcite, and quartz were recognized. From the gate-house 

 other trenches running east and west showed vesicular trap for several 

 hundred feet. A little to the north the quarry which was opened up 

 for the purpose of obtaining rock for the concrete of the dam shows 

 the bowlder-structure and alongside the road running eastward in 

 front of the dam the rock is honeycombed. These last two exposures 

 are still in evidence, but that in the trenches is now covered with tons 

 of earth and masonry, and the only indications of the rock taken out 

 are the bowlders piled in the road embankment. 



I have not traced the prolongation of the valley south of this point. 

 At Upper Montclair the trap quarry of Osborne and MarselHs shows 

 a set of phenomena which probably has some connection with it, 

 but the exact relations are not certain. The contact of trap and 

 sandstone is seen to be very ragged. Angular blocks of sandstone 

 project upward a distance of eighteen inches or two feet into the trap 



