1024 General Notes. [Nov, i: 
This composition is represented by the authors by the formula 
Fe,Na,H,Fe,(Si,O,), = 3FeO.Na,0.2H,O.Fe,0,.9SiO,, in which 
the water is regarded as basic. The authors cannot accept the 
prevalent view that crocidolite is merely a fibrous arfvedsonite. 
Datholite—Mr. Whitfield? has analyzed the datholite from 
Bergen Hill, N. J., determining the boric acid by the Gooch’ 
‘method. His figures are: 
SiO, » FeO CaO B,O; H,O 
35-74 0.31 35-14 22.60 6.14 
corresponding to the formula B,O,.H,0.2CaO.2SiO, = H.CaSi0, 
» the generally accepted formula for this mineral. Ulexite— 
Ulexite, from Rhodes Marsh, Esmeralda County, Nevada, yielded 
the same analyst? the following figures: 
SiO. Cl B,O SO CaO Nao K,O. 4H,0 
iy 2.38 43.20 0.28 acy 0:8 0.44 29.46 
These figures are represented by the formula NaCaB,0, 
+ 6H,O, after making certain allowances for impurities- = 
Siderite (spherosiderite).—This mineral‘ occurs at Baltimore, Md, 
associated with zeolites in the gneiss of the Jones Falls quarries. 
The crystals are small and lenticular in shape. They 
only the forms R and OR, except in one instance, where the neg- 
ative scalenohedron —1{R* is supposed to occur. In these 
crystals the faces are generally rounded, forming a lens-shaped 
body. ae requently two of these lenses are grouped toge 
as to form apparent twins. And further, many pean ate 
together produce a perfect sphere. Analyses of selecte 
by Mr. A. G. Palmer gave,— 
FeO MgO MnO ZnO CO; 
59.63 1.05 0.91 1.72 37-93 
‘on of these rounded forms; 
It is thought that the presence of manganese and zinc 
had some i i 
_ to above) occur. It is described by Professor pii rie T 
‘ splintery, black mineral with a hardness of ab 
specific i 
Metallic acids HO; NY, Sy, ete. (CeTh)O ee 
56.40 I 3.48 11.90 3-85 
Fe | Al,0. VO 
ri 2.00 oF 
r re bi 1887, p. 281. Le i 
- 7 Amer. Chem. Jour., ix., 1887, p. 23, and ii., 1880, p- 247- E E a 
4 Notes on the Minerals eh Bagh the Neighborhood of Baltimore, bY 4 
Williams, Ph.D., Baltimore, 1887, p. 12. - o 
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