> 



k 





%• 



Miner alogkal I^otices. " 593 '. 



r * 



Si 3tl ¥e Mn Ca I&g Na fi; . ign. 



58-92 22-49 0-75 0-60 5'o3 1-87 6 93 0-93 1-64 = 9967 



Oxygen 30-61 10-51 0-23 0*13 1-55 0*72 1-77 0-16 



This result approaches both the andesite of Alsace and the 



lime-oligoclase of Forchhammer. The paste of the same rock 



gave 



Si 31 ffe Ca Jilg ]^a ± ign. 



62-1 7 14-71 7-79 3-30 5-00 4-10 2-04 0-58 = 99*69 



It is remarkable that the part driven off by heat is much less 

 than with the crystals. Its density is 2763; which after fasioa 

 is reduced to 2'486. 



Red Syenite of Egypt, — This syenite^ according to Delesse, 

 consists of quartz, orthoclase, oligoclase, mica and often horn- 

 blende. Mean density 2 63. The orthoclase is of a reddish 

 color. . The feldspar which is commonly referred to oligoclase is 

 usually white, sometimes yellowish or even greenish. The propor- 

 tions of the ingredients are, orthoclase 43, gray quartz 44, white 

 oligoclase 9, black mica 4. — Bull Geol Soc. de France^ vii, 487. 



» 



Mineralogioal Notes from the correspondefice of Prof B. Sil- 

 UMAN, Jr., dated Italy, May and June, 1851. — Prof Scacchi pub- 

 lished in 1849 a memoir on the Canfipania, entitled, ^' Memorie 

 Geologiche sulla Campania," 4to, pp. 131; with 4 plates, Naples. 

 Misenite^ a new species described in this work by Prof Scacchi 

 is a sulphate of potash, having the composition 280^ KO, HO. 



The Stacchite is a silicate of lime and alumina containing: fluo- 

 rine, and occurs in square prisms highly modified. 



Leucite occurs at V'esuvius in the older ejected blocks as well 

 ^s the most recent lavas, and it is observed in some instances un- 

 dergoing a change to Rj^acolitej while still retaining the external 

 form of leucite, and sometimes cavities of ryacolite crystals are 

 formed in the leucite. 



Zircon occurs at Vesuvius in beautiful white and blue octahe- 

 drons in the old ryacolite gangue. Fluor spar occurs in octahe- 

 drons with hornblende in the older lavas* 



Porsterite is identical with anorthite. 



Davyne is regarded by Prof. Scacchi as a variety of Nepheline. 

 The 6-sided prisms are striated longitudinally^ and are modified 

 by a plane on the terminal edges, and another on the lateral; it 

 occurs in a compact pyroxenic gangue, while the Nepheline oc- 

 curs in a gangue of ryacolite. 



Aira^onite is formed in an old mine at Monte Vasa from day 



^4 



¥ 

 b 



to day, at a temperature below that of boiling water. 



Buratite comes from Campiglia in the Marerama Pisena in 

 Tuscany, and not from Volterra. 



Tourmalines of Elba. — In the Grand Duke's collection at 

 Florence there is a specimen U inches square, with four erect 



Lf 



