NJDEP - NJGS - First Annual Report of the Geological Survey of the ...

72"made anywhere on such lines ; the lowest ground will usuallyhave the least thickness of soil or' top dirt. If this dirt isfound too thick for profitable working, other places may betried, for the marl is.worn or. gullied in its upper surface some:times, and the best points for opening may not be hit at thefirst trial; If the lines are run over uneven ground, allowancemust be made for the dip or descent _)f the beds, which is towardsthe southeast, had at the rate. of from twenty to fiftyfeet a mile. This dip will cause bedslto appear further to thenorthwest !fthe ground is higherp and to the southeast if it islower than that started from.COHFCSITION OF THE _ARL, AND TEE CAUSE OF ITS FERTIL-IZING ACTIObr.The value of this deposit as a manure, and the surprisinginfluence ,it has upon the agriculture? of a large district ofcountry, have drawn the attention of scientific farmers andchemists to its composition.Mr. Seybert_ of Philadelphia, made a careful analysis ofthis marl, which was published in 1822, in the second editionof Cl.eaveland's Mineralogy. He foundLten per cent. of potashin it.James Piaree_:Esq.,examined the ma_l beds of New Jersey,and published an interesting account of them in Silliman*sJournal, Volume VI., page 237, in 1823. He attributes thevirtue of marl principally to its shells and other calcareous ingredients.Dr. R. Harlan, in a paper containing remarks on the Geologyof West Jersey, in Volume IV i p_ge 15, of the Transactionsof the Academy of Natural Sciences of Philadelphia,in 1824_attributed its value in some cases to its fossil shells,in others to the iron pyrites .in it_ and in still others to theclay which it contained.A paper on the same subjeet_ Volume ._I, page 59_Trans-NEW JERSEY GEOLOGICAL SURVEY