340 PROCEEDINGS OF THE AMERICAN ACADEMY. 



served by Palache m on crystals from Lake Superior. On one com- 

 bination figured it occurs with (1011) and (16-4-20-15) emphasizing 

 the zone under discussion. The planes were described as smooth and 

 often quite large, evidently furnishing a number of good measurements. 

 The zonal relations are much better than in the previous case and the 

 form should be regarded as well established. 



Hypothetical Scalenohedrons. In the above series the missing terms 

 3 and 2 correspond to the hypothetical forms (8 -4 -12 -7) = (913) 

 and (6-4- 10-5) = (713) respectively. 



(8-4- 12-7) = (913). The pole of this scalenohedron lies in excel- 

 lent zonal relations with frequent and prominent forms, falling in zones 

 [4041 : 2243] and [0221 : 4153] both of which are well marked. It is 

 noteworthy that the scalenohedron recorded by Flink 122 from Lang- 

 ban, Sweden, falls very close to this hypothetical form. It is possible 

 that it should be substituted for the latter. 



(6-4- 10-5) = (713). The pole of this form presents zonal relations 

 which are better than those of the foregoing. It lies in the following 

 well marked zones [0221 : 3142 : 2021], [4041 : 1232] and [0li~2 : 2131]. 



Scalenohedrons- of the Zone [4153 : 0331 : 1120] = [401 : 445 : 101] 



Symbol . 

 fc 



Developing the first portion of this zone between (401) and (445) 

 we have: 



Form \ F l H - » °- V - l - «1 *1 r : 



1401 20-2-7 813 12-2-5 412 32-15-23 423 434 445 



1 

 

 



Referred to N 3 this portion of the zone is incomplete and contains the 

 extra forms 10, 8, 6, and f|, of which the second has been discussed 

 under zone 12. 



121 Palache, loc. cit., Figs. 6 and 19. 



122 Flink, Arkiv. f. Kemi. Min. Geol., 3, 55, Fig. 155 and 156 (1910). 



