Eakle and Rogers — Wilkeite, a New Mineral. 267 



occurs in a few of the specimens which contain the okenite 

 but they have no apparent relation to each other, although of 

 the same general composition. The okenite was also found by 

 D. P. Carlton of Riverside rather uniformly distributed 

 through a blue crystalline limestone containing small crystals 

 of diopside and vesuvianite. The okenite occurs in opaque 

 white subliedral crystals from 1 to 3 mm. in size. A thin 



Wilkeite (W) altering to okenite (O). (50), Crestmore, Biverside Co., Cali- 

 fornia. 



section of this okenite-bearing limestone shows a few minute 

 remnants of wilkeite from which the okenite has conclusively 

 altered. 



It was found to be practically impossible to separate the 

 okenite from the wilkeite and a quantitative analysis of the 

 substance indicated that it was a mixture of the two. There 

 was a loss of sulphate and of lime and a large increase in the 

 silica with the additions of about 10$ of water. 



The change of wilkeite to okenite was probably brought 

 about by magmatic waters, for it is not due to ordinary 

 weathering. 



(A. S. E.) University of California, 

 Berkeley, California. 



(A. F. R.) Stanford University, 

 California. 



