238 PROCEEDINGS OF THE ACADEMY OF 



October 1. 



Dr. Carson, Vice-President, in the chair. 



Eighteen members present. 



The following papers were presented for publication : 



" Catalogue and Synonymy of the Family Astartidse." By 

 Geo. W. Tryon, Jr. 



" Catalogue of the Family Solemyidae." By Geo. W. Tryon, Jr. 



Notice of a Corundum Mine Prof. Leidy remarked that he 



had visited a corundum mine recently opened on the farm of Mr. 

 George Ball, in the vicinity of Unionville, Chester Co., Pa. The 

 accumulation is perhaps the most extraordinary discovered, and 

 its extent yet remains unknown. Detached crystals of corundum 

 have often been found in the ploughed fields and roadsides of the 

 neighborhood, and also masses or boulders of the same material 

 have been discovered on the surface of the ground or buried in 

 the local drift covering the deeper rocks. In several instances 

 boulders of nearly pure corundum have been found in the locality 

 up to several tons in weight. A company was led to seek for this 

 important mineral, and for the purpose sunk a shaft in a neighbor- 

 ing hill of albite, but without success. Mr. John Smedley, an in- 

 telligent farmer, employed by the proprietors of the mine, was led 

 to the discovery of the corundum by noticing the direction of the 

 boulders in the surface drift. Tracing it to the top of the hill, he 

 found it about five feet below the surface. 



The corundum, as exposed to view at the bottom of a trench, 

 appears as the crest of a large body or vein lying between a de- 

 composing gneiss and a white talcose schist. The vein appears to 

 extend in a western direction and towards the east turns at an 

 obtuse angle to the northeast. The exposed portion ma} 7 prob- 

 ably reach twenty or more feet and averages about six feet in 

 depth and five feet in thickness at bottom, and is estimated to 

 contain about fifty tons. How much further the vein extends 

 west and northeast, and how far it reaches in depth and thickness, 

 can only be determined by future mining. It looks as if it pro- 

 mised to be the most valuable deposit of corundum ever found. 



The rock on the south side of the vein is the white talcose 

 schist above mentioned. In immediate contact with the corundum 

 it appears to be metamorphosed into the material described a feu- 

 years ago by our fellow member, Mr. Lea, under the name of 

 Leslej'ite. The schist on the declivity of the hill is contiguous to 

 steatite and serpentine. 



