64 Staten Island Association of Arts and Sciences 



Eleocharis acicularis (L.) R. Sz: S. 



Scirpus debilis Pursh 



Polygonum pennsylvanicum L. 



Polygonmn hydropiperoides Michx. 



Polygonum hydropiper L. 



Isnardia palustris L. 



Bidens laevis (L.) B. S. P. 



Bidens frondosa L. 



It may also be of interest to note that around the margin of 

 the lake, among the plants of recent introduction, were several 

 specimens of Polygonuin orientale L. and Cleome spinosa L., 

 species that are entirely unknown elsewhere in the vicinity and 

 were never before found there. 



Peat, consisting of the roots and other parts of aquatic and 

 semiaquatic plants, was formed to a greater or less extent all 

 around the margin, but especially at the shallow northeast end, 

 where the deposit has a maximum thickness of about seven feet, 

 so far as can be seen in the ditches that have been dug through 

 it to assist in its desiccation, (pl. 4, /. i.) This deposit, I 

 am informed, will be either dug out and removed^ or dried in 

 place and burned if possible, or covered with a blanket of bowlder 

 till sufficient to weight it down and prevent it from breaking 

 loose and floating to the surface when the reservoir is filled with 

 water. The coarser constituents of the peat, or more critically 

 speaking, the incidental debris included in it, consisting of logs, 

 branches, hickory nuts, acorns, etc., may be found more or less 

 lignified and several such specimens were secured. 



The silt deposits inside the peat margin have dried on the 

 surface and cracked (pl. 4, /. 2), and the resulting contraction 

 has caused the hardened surface to slip down the sloping sides 

 toward the middle of the basin, opening crevasses which in 

 places extend down to the old original morainal bottom (pl. 5, 

 /. I, 2). Well defined faults and terraces may also be seen 

 where the contraction and slipping have been most pronounced. 

 The entire mass of silt, in fact, is in process of "creeping" 



