1880.] NATURAL SCIENCES OP PHILADELPHIA. 245 



one end is at right angles to that 

 y at the other end, viz. : 



One crystal had angle at centre, 

 T^SO', angle at edge, 11°15'. 

 (A. K S.) 10^40'. 



5. Jefferson Co., N.Y. Brownish-yellow. (A. N. S.) ll°21'-12°50^ 



6. Yrooman's Lake, Jefferson Co., N. Y. Wine-j'el- 



low. (A.N. S.) 12°45'. 



7. Oxboro', Jefferson Co., N. Y. Light yellow. 



(A. X. S.) 13°12'. 



8. Ottey Lake, Burgess, C. W. Brown hexagonal 



crystals. (W. W. Jefferis). ' 13°20'. 



A crystal from the same locality (J. Willcox) 

 gave for the outer part of crystal, 13°41'; 

 centre of crystal, 11 °23'. 



9. Calumet Is., Canada. Greenish-^^ellow, transpar- 



ent. (A. N. S.) 13°20'-14°18'. 



10. New Hampshire. Reddish-brown, similar to 



Darby Biotite ; nearly uniaxial in thin plates. 13°10'-lt°. 



11. Sparta, N. J. Dark brown; by reflected light 



nearly black. 14°20'. 



12. Yrooman's Lake, Jefferson Co., N. Y. Clear 



pale 3'ellow. Some crA'stals show identical 

 phenomena with those from Hammond, St. 

 Lawrence Co. 



13. St. Denis. "Plumose mica:" brown: thick, 



nebulous hj-perbolas. 



14. "Warwick, N. Y. Dark green; cleaving into 



rhombs ; often mistaken for Biotite. 



15. Pope's Mills, St. Lawrence Co., N. Y. Deep 



reddish-bi'own. (W. W. Jefferis.) 



16. Yesuvius. Black by reflected light, dark red- 



dish-brown in thin plates. With icespar : 

 very opaque. (A. N. S.) 

 It. Clark's Hill, St. Lawrence Co., N. Y. Brown. 

 (W. W. Jefferis.) 



18. Kennett Square, Del. Co., Pa. Brown ; in lime- 



stone. 



19. Edwards, N.Y. Pearly white. (W.W. Jefferis). 



20. Rossie, St. Lawrence Co., N. Y. Yellowish- 



brown. (A.N. S.) 15=52'. 



