REPORT OF THE DIRECTOR AND STATE GEOLOGIST 1900 rll 



stones are in the eame series of altered sediments with the heavy 

 bedded gneisses which oiceur throughout the greater part of the 

 town, receives support from the obtainable fact's of isfratigraphy. 

 As far as could be ascertained, the limestones lie, very generally, 

 closely parallel with the gneisses, and in some cases the two lie 

 together in apparent conformity. 



QUATERNARY FORMATIONS 



The study of the Pleistocene deposits of the eastern part of 

 the state was assigned to Mr J. B. Woodworth of Harvard uni- 

 versity, a specialist of high reputation in glacial geology, who 

 has made a detailed survey of western Long Island and a recon- 

 naissance of the Hudson river valley through Lake Ohamplain 

 to Miontreal in order to consider the evidences of marine sub- 

 sidence. 



The month of June wa,Si spent in making a detailed map of the 

 Oyster Bay and the Hempstead quadrangles on Long Island. 

 This work showed the existence of an early Pleistocene series of 

 gravels and sands, locally folded and involved with disturbed 

 beds of underlying Cetaceous. This Pleistocene formation is 

 thought to be the equivalent in age of McGee's Columbia forma- 

 tion. Besting on it are the morainal deposits of the last or Wis- 

 consin ice epoch with an outwash plain covering the southern 

 half of the island, except for ,a ridge of nonglacial gravels reach- 

 ing the sea at Far Bockaway. North of the main morainal ridge 

 is a line of sand plains with attendant morainal deposits skirting 

 the shore. A water level SO feet above the present sea level is 

 marked in this stage by a well defined delta at Port Washington. 

 In a reconnaissance of the area to the west, another level was 

 determined at about 40 feet. The relation of the 80 foot terrace 

 to contemporaneous sea level has not yet been determined, but the 

 40 foot level appears to be associated with numerous evidences 

 of submergence to that extent early in the period of ice retreat. 

 A detailed report on this work is contained in bulletin 48. 



Subsequent work in determining the limits of the terminal 

 moraines on eastern Long Island was done by Mr J. El Woodnuan 

 under the direction of Mr Woodworth. 



