WHITLOCK. — CRYSTAL FORMS OF CALCITE. 327 



Referred to N 4 this zone fragment is very incomplete and contains 

 the extra form jj. The forms 7 (917) and q ■ (313) have already been 

 discussed under Z 2 and Z 5 respectively. 



U (14- 12-26-5) = (15-1-TT). This scalenohedron was recorded 

 by Whitlock 96 on crystals from Lyon Mountain, N. Y. Although 

 agreeing fairly well with regard to measured and calculated angles 

 this form falls in a rather high normal series. The form must be 

 regarded as somewhat doubtful. 



Hypothetical scalcnohcdrons. — In the above series the missing term 

 2 corresponds to the hypothetical scalenohedron (3- 10-13 -2) = (637). 

 A pole corresponding to these indices would lie at the intersection 

 of zone Z 7 with [3142 : OlIO], [0551 : lOlO] and [1014 :_2791] all of 

 which are fairly well marked with rational forms. (3-10-13-2) should 

 be retained as a hypothetical form. 



Zone 8 = Z 8 . — Scalexohedroxs of the Zone [0112 : 1120] = 

 [110 : 101]. ~^j— (Miller) = 1. Symbol r" 



This zone is susceptible of development without splitting. The 

 recorded forms are as follows : 



Referred to N 4 this zone is incomplete and contains the extra forms 

 fand y. 



a. (5-9-14-8) = (945). This scalenohedron was recorded as 

 Hessenberg 97 on crystals from the Canary Islands. Irby, who has 

 reinvestigated this occurrence, regards the face to which these indices 

 were attached by Hessenberg as utterly indeterminable. The form 

 is very doubtful. 



e : (9-11-20-4) = (11-2-9). This scalenohedron was also deter- 

 mined by Hessenberg 98 on crystals from Matlock, Derbyshire. Irby 



96 Whitlock, H. P., Zeit. f. Kryst., 43, Fig. 5 and 8 (1907). 



97 Hessenberg, F., Min. Notiz., 7 (1866). 



98 Hessenberg, F., Min. Notiz., 4 (1863). 



