CALIFORNIA ACADEMY OF SCIENCES. 



33 



growth of the crystal in some instances became so great as to 

 obliterate all of the terminal edges while preserving the same 

 peculiar habit of the entire crystal. 



One of the geodes just received is of especial interest, from 

 the fact that it contains crystals of colemanite partially converted 

 into a dull, snowy white substance, that probably differs from 

 colemanite only in containing less water. It may prove on ex- 

 amination to be identical in composition with pandermite, in 

 which case it would seem that colemanite may be considered the 

 mother-mineral of pandermite. As already mentioned, pander- 

 mite is said to occur in large quantities associated with cole- 

 manite in Death Valley. 



Two geodes, recently obtained, altogether surpass in dimen- 

 sions that mentioned on p. 5. The more beautiful is 0.15 m. 

 in diameter, and completely lined with brilliant crystals of the 

 larger dimensions stated on p. 4. The other geode is fully 

 0.3 m. in diameter; some of the individual crystals are corre- 

 spondingly larger, but not so clear as those of the former geode. 



One irregular fragment of massive colemanite contains a small 

 fragment of perfect charcoal. 



