450 Hawkins — Mineral Occurrences at Princeton, N, J. 



always surrounds the ilmenite and brookite when the latter min- 

 erals are present, and is itself covered with a layer of calcite, 

 the latter often tilling the balance of the cavity. The barite is 

 found imbedded in calcite, and resting on analcite, but not pen- 

 etrating it. Small pyrite cubes occupy a similar position. 

 There are many cubes of pyrite in the black shales, which 

 occasionally reach a diameter greater than one centimeter. 

 They are always composite, being built up of nearly parallel 

 crystals in rosette-like form. Chlorite of the kind described is 

 a decomposition product of ferromagnesian minerals. The 

 chlorite in the present deposit does not have the appearance of 

 having resulted from the decomposition of another mineral in 

 the present place ; it may have been brought in by solutions. 



Brown University, Providence, R. I. 



