174 PROCEEDINGS OF THE ACADEMY OF [1892. 



MINERAL LOCALITIES OF PHILADELPHIA AND VICINITY. 



BY THEODORE D. RAND, WILLIAM W. JEFFERIS AND 



J. T. M. CARDEZA, M. D. 



The vicinity of Philadelphia has long been famed for the number 

 of its mineral localities and the remarkable abundance and variety 

 of species and specimens. The fact that these have been found chiefly 

 in mining and quarrying operations of limited extent, many of them 

 of short duration, added to the fact that the region has rapidly filled 

 up with a dense population, so that noted localities have been covered 

 with buildings, while others have apparently been exhausted, led 

 one of the writers to suggest that those most familiar with the 

 occurrence of these minerals during the last half century should 

 publish jointly, and in connected form, an account of the localities 

 more nearly complete than any now existing. 



In doing this each has taken the region with which he is most 

 familiar, assisted, however, by the others. No mineral has been 

 mentioned without qualification unless known to one of the writers 

 to have been found at the locality. It is believed that few omissions 

 will be found, but the authors will be thankful for further In- 

 formation from any one knowing additional facts, and such facts will 

 be incorporated in a subsequent paper with due credit. 



The authors desire to express their acknowledgment to Messrs. 

 Samuel Tyson, John Smedley, Joseph Willcox, Edward D. Drown, 

 and Lewis Woolman for valuable information incorporated in these 

 notes. 



The Minerals of Philadelphia and the Territory Adjoin- 

 ing ON THE Northwest. — By Theo. D. Rand. 



A large part of Philadelphia is covered with the Delaware River 

 gravels and clays, but most of the streams have cut through this 

 covering and have exposed the underlying rocks. Owing to the 

 demand for building materials many quarries have been opened, 

 but few of any great extent. The sites of many of these are now 

 covered by buildings. The rocks underlying the gravels and clays 

 are gneisses and mica schists, usually with a strike of about N. 60° 

 E. and a generally northwardly dip ; they are often decomposed to 

 a considerable depth. Their best exposure is along the Schuylkill 

 River. Ascending the Schuylkill, the first exposure occurs at Gray's 

 Ferry: a decomposed, highly feldspathic gneiss, of which the feld- 



