484 PROCEEDINGS OF BALTIMORE MEETING. 



Southeast of the eeries of hills already mentioned remnants of the formation in 

 question are found at lower altitudes. At the same time the areas where the rem- 

 nants occur become larger and less isolated. Still farther to the southeast they 

 become continuous. 



From the topographic distribution of the formation it is clear that its lack of 

 continuity toward the northwest and its continuity toward the southeast are the 

 result of relative elevation. The formation was lifted higher and therefore eroded 

 more to the northwest. To the southeast it was never sufficiently elevated to 

 allow of great erosion. The southward dip of the formation is nearly but not 

 quite as great as that of the Cretaceous beds. Along the east coast its base reaches 

 the sealevel near the mouth of Shark river, in the vicinity of Asbury Park. Across 

 the state the base of the same formation reaches nearly to sealevel in the vicinity 

 of Philadelphia. 



For the present the term Beacon Hill is proposed for this formation because of 

 its characteristic development on the hill of that name near Matawan. 



COMPOSITION 



The Beacon Hill formation is composed of gra,vel and sand in varying propor- 

 tions and relations. On the whole, where existing remnants are thick, there is 

 more sand than gravel. Where they are thin, there is more gravel than sand. 

 This holds true, at least, along the northwestern portions of the area, where the 

 formation occurs in isolated areas. Where the gravel is more conspicuous its 

 abundance is probably the result of the removal of the finer material, the coarser 

 being left behind. Where sand is the more prominent constituent of the forma- 

 tion the original condition of the formation is better represented. 



In constitution, the sand and gravel are essentially quartzose. The gravel con- 

 sists of quartz, chert, flint, silicified fossils, sandstone and, less commonly, of bits 

 of quartzite. Much of the quartz appears to be of vein origin. Some of it may 

 well have come from the abundant vein-fillings in the Hudson Eiver formation in 

 the northern part of the state. In no single instance has this formation been found 

 to contain red shale (Triassic) fragments or pieces of trap, crystalline or gneissic 

 rock of any sort or limestone. Neither does it ever contain, so far as observed, 

 conglomerate or ironstone, both of which are very characteristic constituents of 

 the other members of the " yellow gravel" series. The formation itself is some- 

 times cemented, so as to constitute a conglomerate, but conglomerate does not enter 

 into its make-up as a constituent. In places the gravel is very uniform and fine, 

 the pebbles being mainly half an inch or so in diameter, but it is sometimes much 

 coarser, and frequently carries large cobbles of quartz or sandstone. Rarely it 

 contains blocks (rather than bowlders) of sandstone a foot or more in diameter. 

 Coarse gravel occurs at various horizons from top to bottom of the formation. 



THICKNESS AND EXTENSION 



The thickness of the formation or of its existing remnants varies greatly. In the 

 Navesink highlands it has a maximum thickness of about 100 feet. In the Mount 

 Pleasant hills its greatest thickness can hardly be more than 40 feet. In Pine hill 

 near Perrineville its thickness is about 100 feet, while at mount Holly about 30 feet 

 of it remain. In the Sand hills north of Monmouth Junction there is a thickness 

 of about 100 feet. In the Hominy hills near Farmingdale its thickness must ap- 

 proach 200 feet. The highest of these figures must fall short of the original thick- 

 ness of the formation. 



