RECORDS 469 



SECTION OF GEOLOGY AND MINERALOGY. 



March 19, 1900. 



Section met at 8:15 P. M., Mr. Geo. F. Kunz presiding. 

 The following program was offered : 



Henry B. Kummel, The Palisades. Illustrated by lantern 

 slides. 



John 0. Smock, On the Protection of the Palisades. 



Summary of Papers. 



A summary was read of the information thus far collected in 

 regard to the Geology of the Palisades of the Hudson River, 

 illustrated by numerous views, many of them taken by Mr. 

 Prince, of Orange, N. J. Most of the details of the paper will 

 be found in the 1897 Report of the State Geologist of New 

 Jersey. ()bservers are nearly all agreed that the Palisades are 

 an intrusive trap sheet, which has cooled at great depths. The 

 basal contact is observable at 19 localities, in 15 of which the 

 trap is unconformable upon the sandstone and shales beneath, 

 and is penetrated by tongues of the latter, and in three is ap- 

 parently conformable. The altitude of the lower contact in- 

 creases from the south to the north, where it reaches 200 feet 

 elevation. The upper contact, is seen in six localities. At 

 three of these, dikes penetrating the overlying shales occur at 

 the contacts ; in two the contact is unconformable, and in one 

 conformable. In every instance the beds superjacent to the trap 

 are metamorphosed. In no locality of the Palisades range 

 proper does the upper contact of the trap show any of the 

 characteristics of surface cooling. Well-borings at Fort Lee 

 penetrate 875 feet of the trap, and the total thickness probably 

 exceeds 950 feet, much erosion having taken place. Subsequent 

 to deposition of the overlying sandstones the area was tilted, 

 and the sandstone wasted away by erosion of many streams, 

 the vacant channels of which are still present. The largest of 

 these stream-gaps was one and a half miles wide, and is just 

 north of the New Jersey State boundary. The cutting of gaps 



