RECORDS. 625 



plained. Dr. Merrill illustrated his paper with numerous spec- 

 imens of both the residual clays from the mainland and their 

 transported equivalents from Long Island, together with maps 

 and charts. 



He also gave a brief account of some recent studies regard- 

 ing the peculiar course of the Hudson River in its passage 

 through the Highlands. He pointed out the fact that while the 

 general stream courses of the region are determined by the line 

 of strike, they are modified greatly by fault-lines having a some- 

 what N. W.— S. E; course, transverse to the strike. He next 

 showed that the sharp turn taken by the Hudson in cutting 

 through the Highland range diagonally, instead of conforming 

 to its trend, strongly suggested that in the same way it has here 

 followed a fault-line. 



The paper was discussed with much interest by Professor 

 Dodge and other members. 



Mr. Kunz in his paper described the discovery of native silver 

 at Silver Hill, N. Y., where the metal occurs in peculiar fibrous 

 and minutely crystalline masses. ■ Specimens weighing over ten 

 ounces each of quite pure silver were exhibited. 



Dr. Call read a very comprehensive paper dealing with the 

 origin, history and present condition of the Mammoth Cave, and 

 illustrating his remarks with an extended and beautiful series of 

 lantern slides and maps. 



George F. Kunz, 



Secretary. 



SUB-SECTION OF ANTHROPOLOGY 

 AND PSYCHOLOGY. 



January 23, 1899. 



Section met at 8 P. M., Professor Boas, presiding. The min- 

 utes of the last meeting of Section were read and approved. 

 The following program was then offered : 



Charles H. Judd, The Visual Perception of Linear Dis- 

 tances. 



