WHITLOCK. — CRYSTAL FORMS OF CALCTTE. 297 



This portion of the zone is entirely normal. 

 The forms between (4041) and (7071) are: 



Referred to N 2 this portion of the zone is complete and contains the 

 extra form 7 which would fall in normal series N5. 



x. (13-0-13-2). This rhombohedron was observed by Hofer 19 on 

 crystals from Rauris in Salzburg. On the same occurrence the same 

 author has found the negative rhombohedron (0- 13-13 ■ 1), thus em- 

 phasizing the zone [13-0-I3-2 :0- 13-13- 1] which also contains the 

 forms (6171) and (16-7-23-3). The zone [0-13-13-4 : 13-0-13-2] 

 is also well marked. The form seems quite probable. 



The forms between (7071) and (13-0-13-1) are: 



Referred to No this portion of the zone is complete, the form 8 being 

 extra and falling in normal series, N5. 



c. (8081). This rhombohedron was found by Cesaro 20 on crystals 

 from Rhisnes, Belgium. It is included among the doubtful forms 

 in Rogers 21 list. The fact that the zone [0441-8081] is exceptionally 



19 Hofer, H., Min. Mitth., 12, 487 (1891). 



20 Cesaro, G., Soc. Geol. Belg. Ann., 16, 165 (1889). 



21 Rogers, A. F., S. of M. Quar., 22, 429 (1901). 



