236 



Penfield and Ford — Calaverite. 



Most of the terminal faces, 5, m, u, p, v, u, x and s, are 

 identical with those observed in previous occurrences. Of the 

 new forms, f, g and Jc, the two former fall in a zone with D 

 (304) and v (2-11-10), to which zone also t (13-204) belongs ; 

 compare the stereographic projection, page 242. The_forms 

 s and B x are somewhat doubtful. They may be a (2-10-1) 

 and B (801); compare page 234. 1V62-6, 110 and 17*02 are 

 in a zone, as are also 2-10-1, 110 and 801. 



Occurrence No. 5. — This material includes the crystals from 

 the Prince Albert mine sent to us by Dr. Hillebrand, and pre- 

 viously examined crystallographically by one of us, as already 

 referred to. The crystals average from -J to l mm in diameter 

 and 2 mm in length. Most of them are twinned according to 

 laws which will be described later, but three which show no 

 indication of twinning are represented by figures 21 to 23. 



22 



23 



Figure 21 represents a left-hand termination, the others right- 

 hand ends. One, figure 23, is a doubly terminated crystal, 

 showing similar forms at both extremities of the axis of sym- 

 metry. The prominent forms are those observed on other 

 occurrences. The new forms it and p are each represented by 

 one small face. The symbols of the forms and the measured 

 and calculated angles are as follows : 





Symbols. 



m 



110 



<7 



11-29-5 







13-22-10 



P 



111 



IT 



22-18-27 



V 



296 



p 



44-21-2 



Vertical. 

 00° 00' 

 31 59 

 47 3 

 54 50 

 59 56 

 76 35 

 176 32 



ured. 





Horizontal. 



15° 



58' 



28 



1 



46 



50 



56 



10 



30 



35 



52 



45 



Calculated. 



Vertical. Horizontal. 

 00° 00' 

 32 52 



31° 30£' 

 15 30£ 



47 30£ 28 18 



54 48 

 60 5 



76 38 



176 18 



46 541 



56 31 



30 54 



52 9 



Times 

 Observed. 



3 

 1 



3 

 6 

 1 

 1 

 1 



