ORDER II. GENERA AND SPECIES. 413 



2. Di-PniSMATic. Prismatic. 



Cleavage, P -f co = 118 30'. Pr + 03. Pr. 

 H. = 3-0 ... 3-5, 

 G. = 4-2 ... 4-4. 



Witherite. ii. 119. 



3. PRISMATIC. Prismatic. Pr = 105 6' ; (Pr + oo) 3 



= 77 27'. 

 Cleavage, Pr = 78 18'. Somewhat easier, Pr + co. 



Traces of P oo. 

 H. = 3-0 ... 3-5. 

 G. = 4-1 ... 4-7- 



Heavy. Spar. J. ii, 121. 



4. PRISMATOIDAL. Prismatic. Pr=10358'. (Pr + oo) s 



= 78 35'. 

 Cleavage, Pr = 76 2'. More^pparent, Pr + w. Less 



distinct, P 03. 

 H. = 3-0 ... 3-5. 

 G. = 3-6 ... 4-0. 



Celestine. ii. 126. 



V. LEAD-BARYTE. Rhombohedral, pyramidal, 



prismatic. 

 H. = 2-5 ... 4-0. 

 G. = 6-0 ... 7-3. 



H. above 3-5 : G. = 6-5 and more. 



1. DI-PRISMATIC.. Prismatic. P = 130 (X, 108 28, 



92 19'. 



Cleavage, Pr = 117 13'. (Pr + OD) = 69 20 7 . 

 H. = 3-0 ... 3-5. 

 G. = 6-3 ... 6-6. 



Di-Prismatic Lead-Spar. J. ii, 130. 



2. RHOMBOHEDRAL. Di-rhombohedral. P = 142 12', 



80 44'. 

 Cleavage, P. P -f co. Both very indistinct. 



