SC'HALLBB.] 



Spoduniene from San Diego County. 



271 



It represents the face (110) while the one to the left of it repre- 

 sents the face (110). 



A detailed study of these etch figures shows that they consist 

 of four faces: three side faces and a base. Fig'. 1 gives in detail 

 a view of one of these pits. The bottom or the face lettered m 

 is parallel to the unit prism. The face ,r corresponds to the 

 prism |320|, the face y to [8.14.3| or { 351 J , and the face z 

 to ;11.10.3(. The measurements on which these determina- 

 tions are based, are as follows: 



Measured. Calculated. 



P 



|110j 43° 24' 90" 00' 43° 30' 90° 00' 



S320i 



= A 14= 8.14.3 34 33 81 44 34 20 82 04 



4 





P 



4> 



43° 



24' 



90° 00' 



43° 30' 



55 



49 





54 54 



55 



40 







56 

 55 



09 



53 







34 



33 



81 44 



34 20 



34 



44 



82 19 





32 



33 



82 04 





33 



57 



82 02 











35 01 



40 



44 



80 20 



40 15 



40 



29 



79 25 





41 



06 



80 06 





40 



23 



79 22 





40 



41 



79 48 





= 35 = J 351 J 35 01 82 39 



= --\\ V'=)TT.10.3( 40 44 80 20 40 15 79 47 



For the face y the measurements are approximate for the 

 two symbols |8.14.3j and [35l| and the simpler one may there- 

 fore be chosen. 



Quite frequently the faces m and x grade insensibly into one 

 another or the face m may be entirely lacking. All of the faces 

 are usually very much rounded, making it difficult to obtain any 

 accurate measurements. 



The symbols obtained for the faces of the etch figures do not 

 at all agree with those determined by Dana* on Hiddenite. 



: Amer. Journ. Science, 1S81 (3), 22, 179. 



