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I have entitled the greonsand formatmi, is by far the most 

 interesting portion of the whole deposit, whether we consider the 

 curious properties of its chief constituent, the interesting relations 

 of its numerous fossils, or the highly valuable use as a fertilizing 

 agent, to which a large portion of the stratum is applicable. 



Dipping at a very gentle inclination towards the southeast, its 

 lower layers rise to the surface, and are finally lost towards the 

 northwest, along the irregular denuded margin already referred to 

 as forming the southeastern limit of the underlying potters' clays. 

 Traced in detail, this northwestern boundary of the greensand 

 formation may be described with sufficient accuracy as com- 

 mencing at the southern shore of the Raritan Bay, a little to the 

 northwest of the western termination of the Highlands of Neve- 

 sink, about the mouth of Compton's creek. Its course from this 

 point, where the underlying strata are seen to rise above the level 

 of the water, is a little south of west, past the small village of 

 Mount Pleasant, to Deep run. From Deep run, the visible limit 

 of the greensand takes a nearly south direction for nearly two 

 miles, and then a westerly one to the Matchaponix creek, which 

 it crosses about two miles southeast of Spotswood. It next 

 crosses the Manalapan, two miles above the mills marked on the 

 map as Mount's, previously sweeping in a somewhat concave 

 line to the southeast. Between the Manalapan and the Millstone 

 streams, it presents a similar curve towards the southeast, 

 appearing on the latter about half a mile above the spot called 

 the Red Tavern. Thence, bending as before, first to the south 

 and then to the west, it crosses Rocky brook, half a mile below 

 Millford. From this point its course is first south to Empty run, 

 then southwest to Doctor's creek, a little above Allentown, and 

 then west-southwest along the southern side of the same stream 

 to Crosswick's creek, which it passes about half a mile above the 

 little village called Groveville. From Crosswick's creek to Bur- 

 lington creek the line of the greensand is nearly straight, crossing 

 Black's, Craft's, and Burlington creeks, each at points about one 

 mile and a half from the Delaware. Passing the latter stream, it 

 recedes somewhat from the river, meeting Rancocus creek about 

 four miles above its mouth, near Franklin Park and Pensaukin 

 creek, one mile west of Moorestown. Its course next, is a little 

 more westward, to Cooper's creek, down which the stratum 



