A GEOLOGICAL HISTORY. 27 



and slipped from its natural place,) near the old 

 post road, and near where 51st Street crosses the 

 3rd Avenue ; this large flat piece of Gneiss, lies 

 supported against the rock of which it once formed 

 the top, presenting the appearance of a cavern, 

 particularly when it was surrounded by trees and 

 undershrubs, overgrown and entangled with briers, 

 giving it a deep shade. 



Fresh water ponds.* — There were three or more 

 fresh water ponds on this island : the first and largest, 

 was called the Kolckf (Collect) by the worthy Knick- 



* In these ponds, were several kinds of fish, one peculiar to fresh water 

 — viz. (Labrus Auritus, of Mitchill,) or fresh water sun-fish; the other 

 species were common to both fresh and salt water. The common eel (An- 

 guilla Vulgaris, of Mitchill,) three varieties of Killifish, (Esox pisculen- 

 tus, of Mitchill) one of which, I do not recollect having seen any where 

 else, it was called by the boys, " Yellow-bellied Cobbler," on account of 

 its abdomen being of a golden colour. The " stickle back" (Gasterosteus 

 quadracus, of Mitchill) was found in the powder-house pond, but did not 

 inhabit " the Collect." 



t This pond, when frozen over, was a most delightful spot for skating, 

 and sliding, to which all the boys of former days repaired, some hundred 

 might be seen amusing themselves, forgetting in the ardour of play the 

 intense cold of the weather; but woe to those who were caught there on 

 Sunday; old Delamater, old Thompson, and afterwards old Hays, then 

 a young man, (the Sunday constables of that time,) gave them more ter- 

 ror, with the thoughts of Bridewell, than all the pleasure was worth. 

 At the great undertaking of filling up this pond, and levelling the sur- 

 rounding hills, a curious fact took place which should be noticed here. 

 The specific gravity of the sand and gravel of the hill, was so much 

 greater than the mud and sediment of the pond, that it pushed up in its 

 centre large islands of this sediment, exposing a soft quagmire, and the 



