f 



20 University of California Publications in Geology. L VoL - 7 



are very thin compared to their lateral dimensions (fig. 10). The 

 forms and angles measured and calculated are as follows : 



c (001) 

 e (101) 

 u (102) 



Calculated 

 57°37' 

 38 15 



Mineralogical Laboratory, 



University of California. 



Transmitted March 4, 1912. 



(001) : (101) 57°31' 

 (001) : (102) 37 56 



