RECORDS OF MEETINGS OF 1908 501 



SECTION OF GEOLOGY AND MINERALOGY. 



December 7, 1908. 



Section met at 8:15 P. M., Vice-President Grabau presiding. 



Eighty persons were present. 



The minutes of the last meeting of the Section were read and approved. 



The following program was then offered: 



James F. Kemp, Our Knowledge of the Filled Channel of the 



Hudson in the Highlands and the Submerged 

 Gorge on the Continental Shelf. 



Charles P. Berkey, A Suminl^ry of an Investigation into the Structural 



Geology of Southern Manhattan and the 

 Condition of the East River Channel. 



Edmund Otis Hovey, Some of the Latest Results of Explorations in 



THE Hudson River at New York City. 



Summary of Papers. 



Professor Kemp gave a summary of the results of borings in the channels 

 and buried valleys of the Hudson and its tributaries, all pointing to a former 

 elevation of this portion of the continent. The speaker showed that a much 

 greater depth is now known in the Hudson itself at Storm King Mountain 

 than at any other point in the whole drainage system except on the submerged 

 continental shelf, where soundings have proven a very deep gorge which 

 probably represents the Pre-Pleistocene Hudson channel. 



Dr. Berkey exhibited the results indicated in his paper on a large scale 

 map of Southern Manhattan. The work is based upon personal examina- 

 tion of several hundred drill borings with an attempt to identify the rocks 

 penetrated. It seems certain that southern Manhattan is not wholly schist, 

 as formerly mapped, but that the east side is made up of the usual succession 

 of folded Fordham gneiss, Inwood limestone and Manhattan schist. 



The East River channel is, in comparison with the Hudson, a very unim- 

 portant one. In this lower portion, it is essentially a very small drowned 

 tributary. 



Dr. Hovey exhibited and discussed borings made by the engineers for the 

 Pennsylvania Railroad Tunnel across the Hudson on the line of Thirty- 

 second Street. He showed that bed rock has been found at approximately 



