1818.] VICINITY OF PHILADELPHIA. 469 



tallized, but I have never witnessed it. Siilphuret of iron 

 and phosphat of lime accompany it. 



Red Oxide of Titanium. Rutile, W. Titane oxide, H. 



In the granular limestone of London grove, Chester 

 county, particularly on the property of Mr. John Jackson, 

 this mineral occurs crystaUized in prisms, geniculated, in 

 angular and broken pieces, and rolled. Colour, generally 

 that of biood red to brown. 



Silica calcareous Oxide of Titanium. Riitilite. W. 

 Titane siliceo calcaire. H. 



Mr. Vanuxem and myself, about eighteen months 

 since, discovered this species, imbedded in the horn- 

 blende rocks of the quarry at the end of the canal road. 

 Some specimens are finely crystallized in very low octa- 

 edrons, nearly an inch over, with the obtuse angles trun- 

 cated. Colour, a dull waxy yellow. Mr. S. Conrad had 

 some years previous, observed it in small quantities, at the 

 falls of Schuylkill. 



EARTHY MINERALS. 



Zircon. Zirkon, W. Zircon, H. 



This mineral exists in several places of our neigh- 

 bourhood. It was first discovered at the falls of the De- 

 laAvare at Trenton, about twenty yards above the eastern 

 abutment of the bridge, in gneiss, by Mr. S, Conrad. 

 Crystals, generally small four-sided prisms, of a dark 

 brownish red, imbedded in pale blue quartz, and green- 

 ish feldspar. Another locality of this mineral was disco- 

 vered by Mr» Vanuxem and myself, about t^vo years 



