A GEOLOGICAL HISTORY. 19 



distributing Croton Reservoir, in 42nd Street, and 

 at Harlem flats, and on the Kingsbridge road, near 

 the 12 mile stone, it is of the greatest depth : 

 (it is coloured on the map as a reddish-brown.) 

 In this wash, as it is called by some, are 

 found types of all the rocks of the valley of 

 the Hudson. As seen when taken in mass, its co- 

 lour are a mixture of yellow, red, gray, and 

 brown ; it is a compound of boulders, gravel, sand 

 and silicious clay. In its structure it differs ; in 

 some places it is a fine yellow sand lying on the 

 top, as around the region of Broadway and 8th 

 Street, (old Sandy Hill Lane,) and on part of Mr. 

 Bradhurst's farm, and on the Kingsbridge road 

 between the 7th and 8th mile stone. Part of a hill 

 of this sand may still be seen at Mr. Brevoort's 

 place, at 10th Street, west side of Broadway, This 

 kind of sand,* whenever seen, always lies on top. 

 In describing the hills which have been dug 

 down, I shall begin with the ridge,f which com- 

 menced at Warren Street, ran parallel with the 



* This same kind of sand forms the earthy part of Bedlow's Island, 

 the peninsula of Paulus Hook, (Jersey City,) Hoboken, and a large field 

 near Hackensack, N. J., and also large areas on the south part of Long 

 Island ; and always lies on the top of the coarser Diluvium, and is never 

 more than four or five feet in depth from the top. 



t On a hill near where the corner of Provost and Varick Street now 

 is, there was a revolutionary fort still standing in 1797, in which some of 

 the old cannon lay dismounted. 



