1885. | Mineralogy and Petrography. 395 
_ Analysis of the more greenish or bluish kind gave : 
Sio, FeO, FeO Al,0, CaO MgO. H,O 
93-43 2.41 1.43 0.23 0.13 0.22 0.82 
Total 98.67 
They announce it as the result of a microscopic examination 
that the mineral is not a pseudomorph, but that the silica has 
been deposited between the fibers, which were already more or 
less altered, enclosing them in a hard transparent matrix. 
PETROGRAPHICAL Notes. — Becke! gives, in good form, the 
methods for microscopically distinguishing augite and bronzite. 
Scharizer, of Vienna, has studied the hornblende from Jan 
Mayen, and appends some interesting remarks regarding the 
general chemical constitution of the aluminous hornblendes.? 
He regards them as isomorphous mixtures of typical actinolite 
(Mg Fe), Ca Si Si, Op and a molecule R, R, Si; O,., to which he 
applies Breithaupt’s old name, syntagmatite. Merian contrib- 
utes an interesting attempt to trace the relation between the com- 
position of an eruptive rock and that of the pyroxene mineral 
which it contains. J. Eliot Wolff gives a short note on the 
occurrence of nephelinite and nepheline-tephrite, both rich in a 
mineral of the sodalite group and often containing olivine, in the 
razy mountains, an isolated range north of the Yellowstone 
river, in Montana. These rocks have never before been observed 
within the limits of the U. S. 
ery, by J. S. Diller, of a new type of volcanic rock—a_ hyper- 
sthene basalt—on Mt. Thielson, Oregon’ on the surface of which 
fulgurites were found to be largely developed. This rock is new, 
but exactly fills a vacancy in the accepted rock classification —— 
€ same writer mentions peridotites which break through the 
Carboniferous strata of Kentucky in the form of dykes, enclosing 
fragments of the adjacent rock. He also finds, upon microscopic 
given an elaborate microscopic study of the volcanic and cosmic 
dust that forms so large a portion of the deepest ocean deposits. 
—Holst and Ejichstadt® have described from _Slattmossa, in 
Sweden, an amphibole granite having a beautiful spherulitic 
Structure not inferior to that of the well known “ napoleonite 
or “ corsite,” a nodular diorite from Corsica, described by Vogel- 
'Tschermak Min. Pet. Mittheilungen, V, 1883, p. 527. 
* Neues Jahrbuch fiir Min, etc.. 1884, Il, p. 143. 
. Four. Science, Oct. 1884, p. 253- 
€ Science, V, pp. 65 and 66, Jan. 23, 1885. 
*Bull. Mus. Roy. d’Hist. Nat. d. Belgique, II, 1884, 1-24. Nature, April 17, 
I 
®Geol. Féren. i. Stockholm Forh., 1884, Vol. vit, p. 134. 
