220 PROCEEDINGS OP THE ACADEMY OF [1880. 



and west from each oUier, the strike of which was, wherever ob- 

 servable, more N. E. and S. W. than the line joining them, thus 

 agreeing in stnicture with what Prof. Rogers states of the trap 

 dykes north of the serpentine in Chester County. He also called 

 attention to the existence of two trap dykes or two branches of 

 that extending through the Gulf Valley, and to curious markings 

 in quartz rock in the vicinity', suggestive of fossils in a formation 

 reaarded as azoic. 



-o" 



June 8. 



The President, Dr. Ruschenberger, in the chair. 



Twentj^-two persons jtresent. 



A paper entitled " On the Development of Lemna minor," by 

 Wm. Barbeck, was presented for publication. 



June 15. 

 The President, Dr. Ruschenberger, in the chair. 



Eighteen persons present. 



A paper entitled " A Bibliographical Catalogue of the Genus 

 Partula, with observations on the Species," b}' W. D. Hartman, 

 M. D., was presented for publication. 



June 22. 

 The President, Dr. Ruschenberger, in the chair. 



Eighteen persons present. 



The deaths of AVni. G. E. Agnew and Morris L. Ilallowell, 

 members, were announced. 



June 29. 

 The President, Dr. Ruschenberger, in the chair. 



Eleven persons present. 



The deaths of B. F, Lautenbach, M. D., and Wm. Kent Gilbert, 

 M. D., members, were announced. 



On some Hoviologies in Bnnodont Dentition — Dr. Harrison 

 Allen, in speaking of the teeth of the Carnivora, Insectivora and 

 Chiroptera, dwelt upon the forms of the canines and premolars as 



