172 (I'cologij of J^irliiDOiKl Cuuiifij. X. Y. 



drift-liills or the nioraino. wliicli cover all tlie territory assumed 

 to be underlaid by the clays, except that portion where pits 

 have been excavated, which is northwest of the moraine, the ice- 

 sheet having flowed over, or perhaps jjartly around it. 



Interstratified with, and overlying the clays and sands, there 

 are found thin beds of Limonite iron ore of limited extent ; this 

 substance frequently cements the sand and gravel, and forms a 

 conglomerate of variable coarseness. Hitherto this ii'on ore has 

 not often been discovered in sufficient quantities or of sufficient 

 purit)^ to warrant its use in the manufacture of iron. Lignite 

 and ])yrites are frequently fouiid in the clay excavations. 



The former sul)stance may also bo seen on the shore of Artlmr 

 Kill near Kossville, and in a ravine a little northeast of the 

 village, after slides of the banks occur ; it is generally impreg- 

 nated with the pyrites, and with copperas after exposure to the 

 air. As the lignite dries, it cracks up into little pieces, thus 

 destroying the texture of the fossil wood composing it. and 

 making it very difficult to retain good si)ccimens. No fossil 

 leaves or shells have been taken from tlio clays of Staten Island, 

 but it is not improbable that they will be found at some future 

 time, when the excavations are mcn'e advanced than at present. 

 They Jire more likely to be found in buif oi- dai'k colored clays 

 than in lire-clay. The leaves are of great interest, as they rc- 

 ])resent the first ai)i)earance of angiosi)ermous plants on the 

 earth. Large quantities of them have been collected at 8outh 

 Amboy and other places in the clay district of New Jersey. 



Origi)i of these Depoxifs. — As these beds ai"e composed of 

 fragments of quartz, mica and clay, or decomposed feldspar, it 

 is evident that they are the ]n'oducts of the disintegration of 

 gneissic or granitic rocks. That they have not been formed in 

 place., but have been dei)osited from suspension in water, is 

 proved by their stratification and by the assorted state of the 

 materials composing them. That the waters which deposited 

 the clays were fresh, is indicated by the absence of fossil marine 

 organisms, and the presence of sliclls apparently allied to the 

 modern fresh-water genera, in the clays of New Jejsey. 



There has been considerable discussion in regard to the posi- 

 tion of the gneissic rocks ; it Avonld seem probable that the 



