3<0 CALIFORNIA ACADEMY OF SCIENCES. 



The few quartz crystals accompanying the pyrite and albite in 

 the drusy cavities were the latest formed. They are the usual 

 combination of prism with positive and negative primitive rhom- 

 loohedrons and small rhombic faces of £ (2 P 2). 



Pyrite from New Almaden. 



In the latter part of 1884, I received from Mr. Engene Hoefer, 

 a former student of mine, at present mine surveyer at New Alma- 

 den, a beautiful little specimen from the recent workings of the 

 quicksilver deposit, showing in a small cavity lined with crystal- 

 lized rhombohedrons (K) of dolomite, four or live delicate speiss 

 yellow needles quite similar to those from the Stanislaus mine, 

 radiating from a common point beneath the dolomite crystals, 

 piercing the latter, and projecting freely into the cavity. I had 

 refrainedfrom breaking one of the needles until more of the 

 material had been obtained. After studying the Stanislaus crys- 

 tals, however, I detached and measured the angles on one of these 

 needles. The cross-section was a nearly perfect hexagon. The 



angles showed that four of the faces belong to the new pentagonal 



oo I 

 dodecahedron c 1 = — — k— n (470), while the other two were 



faces of the cube a. The following angles were measured: 



OBSERVED. CALCULATED. 



Vivianite from Camptonville, Yuba County, California. 



The only locality in California from which crystallized Vivian- 

 ite has been obtained, is Camptonville, Yuba County. 



The University Mineralogical Museum possesses but a single 

 specimen from this locality, collected many years ago by Mr. 

 C. D. Voy, out of a clay stratum in the auriferous gravel at Camp- 

 tonville. It is 100 mm. long and 40 mm. wide, entirely cov- 

 ered on one side with thick tabular vivianite crystals, the largest 



