1910.] NATURAL SCIENCES OF PHILADELPHIA. 455 



quartz veins in epidotized layers in the basalt lava. It is believed that 

 the metal was originally distributed throughout this rock and has 

 been concentrated, like the associated quartz, in obedience to the 

 principle that large crystals grow at the expense of small ones, that 

 the reduction to metallic copper was brought about by the ferrous iron 

 of the rock constituents, that the copper was transported as a dilute 

 solution of free metal by the circulating waters, and that the associa- 

 tion with epidote is of physical rather than of chemical significance, in 

 that the epidotized layers were the only ones of sufficiently resistant 

 character to permit of the development of open cracks during the 

 regional metamorphism. The workableness of the deposits depends 

 upon the continuity of these epidote-bearing layers and their included 

 quartz veins in depth, but since no explanation can be given for the 

 epidotization of certain layers of the rock it seems impossible to predict 

 this from present indications, and extended drilling is thought to be 

 the only way to settle the question as to the future of the district. 



Silas L. Schumo, on the pot holes of the Falls of Schuylkill, illus- 

 trated by photographs. (No abstract.) 



F. Lynwood Garrison, on the copper deposit and mining operation 

 near Bound Brook, N. J. (No abstract.) 



Henry Leffman, M.D., exhibited the effect of polarized light on 

 preparations of rock-sections by the Lumiere color-process. 



Edgar Madison Ledyard was elected a member. 



The following were ordered to be printed: 



