446 Hawkins — Mineral Occurrences at Princeton, i\T. J. 



Art. XXXYIII. — Some Interesting Mineral Occurrences at 

 Princeton, J\T. J. ; by Alfred C. Hawkins. 



[Contributions from the Geological Department of Princeton University.] 



Recent geological investigations undertaken by the writer 

 in the vicinity of Princeton, N. J., have brought to light the 

 presence of certain unusual mineral deposits there, for some 

 time known to exist, but not, until now, studied in any detail. 

 The mineral species afforded are interesting both in their 



Fig. 1. 



Pig. 2. 



•b 



Fig. 3. 



Fig. 1, Brookite. Fig. 2, Barite. 



Fig. 3, Ilmenite. 



geological and mineralogical associations and in their crystallo- 

 graphic development. 



The rocks in the section of New Jesrey herein mentioned are 

 the shales and sandstones, with associated diabase, belonging to 

 the Triassic system. Quarries within the town of Princeton 

 have recently exposed intensely breCciated areas of very lim- 

 ited extent, marking crushed zones in the dense sandstone 

 layers. Within these breccias the mineral species here de- 

 scribed occur, occupying the spaces between the angular grains 

 of the crushed and shattered rock. The crystals obtained are 

 small but often exceedingly brilliant and gem-like. 



