6 CALIFORNIA ACADEMY OF SCIENCES. 



The forms observed are the following: 



m = odPoo (010) 



n = coPoo (100) 



g = P (001) 



H = ooP3(130) 



J = oo P^ (370) 



z = co P 2 (120) 



P = co Pi£ (10.19.0) 



s = co P (110) 



t = co P 2 (210) 



c = P co (011) 



a = 2 Poo (021) 



?/ = P(T11) 

 d = 2P (221) 



6 = — P (111) 

 6 = — 3P(331) 

 A =— V-P (19-19.6) 

 o = 2 P 2(211) 

 £ = 3 P | (231) 

 Q = 4 P 2 (241) 

 r = ;|P f(232) 

 d = 2 P 2 (T21) 

 a; = 3 P 3 (T31) 

 co = — 3P3(131) 

 @ = 3 P 3 (311) 

 B = 4 P 4 (111) 

 k = — 3P3(311) 

 U = 6 Poo (601) 

 V = 4 P oo (101) 

 fc = 2 P oo (201) 

 t = Poo (101) 

 A = — 2Pcc(201)* 



Of these forms s (oo P), c (P co), a (2 P co ), y (P), u (2 P), 

 and d(2P 2), were observed on all the crystals examined, 



*See Appendix U. 



