A GEOLOGICAL HISTORY. 35 



width, now they are almost all filled over with the 

 earth of the surrounding hills, and built upon. 



There are some salt meadows yet beyond the 

 six mile stone, on the East River, which are some- 

 what altered. 



At the foot of 30th Street, near the Hudson 

 River, was a small salt marsh now all covered over 

 with earth from the surrounding hills. There is 

 yet a salt marsh, which has had no improvements 

 on it, but the filling up and grading of the 10th 

 Avenue, this is on the North River, near the foot 

 of 42nd Street, at the upper end of the " Timber 

 basin :" and there are a few other formations of 

 the same kind near Kingsbridge. 



There were many small streams or brooks on 

 the Island, but none of importance, if we except 

 the one called Harlem creek, which runs through 

 the salt marsh, at the six mile stone ; this creek has 

 two or three branches, one of which follows along 

 the lowlands to near Manhattanville, where some 

 projectors in a speculation commenced a few 

 years since, a canal, which they left when partly 

 finished. 



In digging down the hills of this Island, to fill 

 up the swamps and low grounds, there has been a 

 fine chance, for the geologist to observe, how the 

 materials of this Diluvium were deposited ; in some 



