Mineralogy and Petrography. 929 
with chabasite, has resulted from the alteration of the plagioclase. 
—In Blum’s “ Pseudomorphosen”! mention is made of a grani 
at Vordorf in the Fichtelgebirge, in which the flesh-red orthoclase 
is partially altered into epidote. Sandberger,’ who has found blocks 
of the same rock, states that the epidote is more likely an alteration 
product of hornblende or augite, as it is associated with asbestus, 
while the red orthoclase is still fresh A grammatite rock occurs,’ 
interstratified with phyllite, in the Bohemian Fichtelgebirge, between 
lein- Wenden and Sichersreuth.—The third paper on the rocks of 
the Cortlandt Series, in the Hudson river, embraces‘ the treatment 
of the gabbros and diorites associated with the peridotites and 
norites which have been described in another place. The gabbros 
present no peculiar features other than the granulation of some of 
their constituents. Two types of diorite are distinguished. One, 
containing brown hornblende, tends to pass into gabbro, norite, or 
hornblendite. The other, containing green hornlende, is closely 
related to mica-bearing rocks. The mica-diorites (Dana’s soda- 
granites) are essentially coarse-grained aggregates of plagioclase and 
biotite, with often a little orthoclase and quartz, and sometimes 
garnet as a metamorphic mineral. The plagioclase has a specific 
gravity between 2.67 and 2.65, and is sometimes twinned, while at 
other times it is entirely free from twinning lamelle. The most 
noticeable feature in the rock is the occurrence in it of a pale green, 
non-pleochroic epidute, which appears to be original. The mineral 
is generally without terminations. It is strongly corroded on its 
ges as if eaten into by a liquid magma. The paper closes with 
a graphic representation of the close relations, which the author, 
Dr, Williams, has found to exist between the various eruptive 
members of this series. 
MINERALOGICAL News.—In Douglas Co., Oregon, is a bed of 
nickel silicate, resembling garnierite, whose origin has been deter- 
mined with some degree of certainty by Prof. Clarke.’ A pure. 
specimen of the mineral was found to have the composition :— 
TiO MgO SiO, Al,0,+Fe,0, Loss on ign. Lossat110° 
7.57 10.56 44.73 1.18 6.99 8.87 
‘ iii., p. 120. 
3s Neues. Jahrb. f. Min., ete., 1888, i., p. 208. — 
, Sandberger : Neues Jahrb. f. Min., etc., 1888, ii., p. 202. 
, Amer. Jour. Sci., June, 1888, xxxv., p. 438. 
p Amer, N aturalist, June, 1887, p. . 
Amer. Jour, Sci., xxxv., 1888, p. 483. 
