THE PLANT WORLD. 185 



adjacent hillsides. Theoretically such sediments must have been in 

 process of accumulation ev^er since the depressions were first formed, 

 that is since the final recession of the ice sheet from the region, so 

 that the bottom layers should represent deposits of Quaternary age. 



One of these swamps had often claimed my attention by reason of 

 it being an excellent botanical collecting ground, consisting of a small 

 pool of water near the middle, around which was a margin of SjJiag- 

 nuni, interspersed with tussocks of Carex and Juncus. 



In the development of the land for cemetery purposes it was de- 

 cided to clean out the swamp and convert it into a pond, for a better 

 landscape effect, and in the progress of this work the entire series of 

 sediments was removed, down to the bottom of the morainal basin. 



The surface consisted of peat and black organic mud, such as may 

 be seen in almost any swamp where there is a growth of Sphagnum 

 and an accumulation of decavino; vegetation. Below this however was 

 a more sand}" deposit, distinctly stratified, containing a number of logs 

 and branches, partly lignitised, while below these, at a depth of about 

 ten feet, was a stratum in which were finer vegetable fragments, large- 

 ly consisting of cone scales and some perfect cones of a gymnosperm. 



This was the first intimation of different conditions having pre- 

 vailed at some period from those now in existence in the vicinity, as 

 the present forest growth is entirely angiospermous and was such ever 

 since the time of the earliest historical records of the Island. Fur- 

 thermore, a careful examination of the cones showed them to belong 

 to the White Spruce {Plceci Canadensis B. S. P.) — a tree of northern 

 range, which does not extend further south than northern New York, 

 Vermont, New Hampshire and Maine. 



This was the fact discovered and the obvious inference drawn was 

 that the portion of the deposits in which the cones were found must 

 represent material which had accumulated when the climate was con- 

 siderably colder than now obtains on Staten Island and that it was per- 

 haps of Quaternar}' age. 



The evidence, however, was not conclusive, so a careful watch was 

 maintained for any future developments, and finally, close to the bot- 

 tom, at a depth of about twenty -three feet, the workmen unearthed 

 some hard fragments which turned out to be pieces of a Mastodon's 

 molar and the required evidence was at hand, 



Columbia University, Dec. 5, 1900. 



