118 



NEW YORK STATE MUSEUM 



by elevation of an area of land around the basin, which would 

 afford more siliceous matter. 



An elevation would be accompanied by an acceleration of the 

 streams, and much of the siliceous matter transported by them 

 would be carried farther out into the estuary and spread over its 

 bottom, while the tiner clayey sediment would be carried out to 

 sea. A readvance of the ice, it would seem, would likewise 

 cause an acceleration of the streams, and with the results stated 

 above. 



To account for the isolated bowlders in the clay it seems 

 highly probable that icebergs or icefloes having stones and dirt 

 imprisoned within their mass detached themselves from the 

 retreating glacier, and, floating down the estuary to the sea, 

 dropped their burdens. 



The unstratified material found with it and in some cases over- 

 lying the stratified delta deposits is a matter of interest as con- 

 cerns its origin. Three things may be noticed regarding it. 



1. The material is sand, pebbles and cobblestones lying mixed 

 together without any separation of the coarse from the fine.* 



2 The pebbles and stone are rounded and do not show any 

 scratches. 



3 The materials are mostly of the same character as the rocks 

 of the vicinity. 



Now as the land rose from its submergence the velocity and 

 with it the transporting power of the streams would increase, 

 washing down quantities of large stones and gravel. Dr. Merrill 

 considers that a rapid flow of water took place down through 

 the Hudson Yalley in the late Quaternary. This water 

 must have come down through the valleys of the tributary 

 streams, having a much greater velocity in their valleys than it 

 would have after it turned into the Hudson Valley, and the 

 checking of its velocity as it reached the Hudson would cause 

 the deposition of the greater part of its load. A large stream 

 rushing down the valley of the Fishkill would drop its burden 

 specially below it, where we find them heaviest as the flow of the 

 water was toward the south. Again, Peek's Kill would behave 

 in a similar manner. 



A curious and interesting phenomenon is the crumpling of the 

 clay at many localities. This disturbance often extends through 



* The only locality where stratification was observable was at Timoney's yard near Dutchess 

 Junction 



