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so abundantly introduced into the marl stratum, as to act the 

 part extensively performed by it in nature, of a cement, bind- 

 ing firmly together into a semi-rocky mass, the materials with 

 which it is in contact. When this occurs, the marl is often ren- 

 dered too hard to be excavated by the ordinary implements. 

 When indurated or solidified from this cause, it is most commonly 

 in the form of large round concretions, from the size of a bushel 

 to that of a barrel, lying in horizontal layers, generally near the 

 top of the stratum. These masses thrown out and exposed to the 

 frosts of a winter, most usually crumble down into the friable 

 state so essential to form a useful marl ; and the material seems 

 to be not in any way impaired in its virtues, from having been 

 united in such firm cohesion. When the cementing action has 

 proceeded farther, a regular stratum of indurated greensand rock 

 exhibits itself Such may be seen in some portions of the clifis 

 on the bay side in the Nevesink hills, large blocks of it strewing 

 the beach, and offering some beautiful specimens of a fine brown- 

 ish-green rock, in which the green granules are dispersed through 

 a cement (or paste), deeply coloured by oxide of iron, giving the 

 whole a pleasing variety of tint. 



The above descriptions embrace the principal changes which 

 the materials of the greensand formation seem to have undergone 

 since their original deposition. They claim attention, not merely 

 for the elucidation they aflford of some of nature's most impor- 

 tant operations, performed in her quiet laboratory by her silent 

 but potent chemistry, but for the valuable practical suggestions 

 they furnish concerning the greensand deposit in its interesting 

 light of a fertilizer of the soil. 



The total thickness of the greensand formation, estimating it 

 from the bottom of the lowermost layers abounding in the green 

 granular mineral to the overlying yellow ferruginous sands, or 

 the limestone bed when this is present, may be stated approxi- 

 mately at about one hundred feet. The only place in the whole 

 district where it is practicable to ascertain, with any approach to 

 accuracy, either the depth of the formation, or the relative situa- 

 tion and number of the separate beds which it comprises, is along 

 the shore of Sandy Hook bay in the cliffs of the Nevesink high- 

 lands. This, the only coast section of the strata, is still an im- 

 perfect one ; large masses of the upper beds, fallen from above, 



