CERUSSITE CRYSTALS FROM BROKEN HILL AND MULDIVA. 



297 



Group III. — This is very similar to Group II and does 

 not require particular description. The orientation is as 

 follows : — 



Segment. 



v c 



Limits. 



Number of 

 Observations. 



+. 



I 



II 



III 



IV 



351° 



48 19 

 109 5 

 166 14 



350°59'- 351° 2 



48 14 - 48 26 



108 59 - 109 6 



166 11 - 166 17 



5 

 6 

 5 



2 



o° d 



57 19 

 118 5 

 175 14 



Thus I is twinned to II on r (meas. 57° 19', calc. 57° 18') 

 and III to IV on r (meas. 57° 9) while bi A b 3 = 61° 55' and 

 b 2 a b 4 = 62° 5'. The direction of divergence is the same as 

 before and is in accordance with Goldschmidt's hypothesis. 



Group IV (Plate LIT, fig. 4, Text Fig. 3).— This is 

 essentially similar to the two preceding groups, but the 

 segments are united in a different manner. 



Segment. 



v 



Limit. 



Number of 

 Observations. 



<£o 



I 



II 



III 



IV 



(V 



72° 52 

 130 7 

 250 41 

 128 



72° 48 - 72° 56 

 130 5 - 130 9 

 250 34 - 250 46 

 127 56 - 128 4 



4 



7 

 7 

 7 



o / 





 57 15 



177 49 

 55 8 



117 14) 



vrtti* 



I do' 



Fig. 3. 



