1216 General Notes. [ December, 
see no reason why a single, homogeneous individual of the former 
mineral should not replace one of the latter. He furthermore 
thinks that such secondary hornblende (which cannot be regarded 
as an alteration product in the common sense), should be used 
for purposes of rock classification, and suggests names as 
uralitite, uralite-diabase, uralite-gabbro, etc., to be employed, of 
course, only where the secondary nature of the hornblende was 
beyond doubt. 
culated to throw light upon the original form of the minerals 
of the more basic massive rocks. Many of these, like labra- 
dorite, olivine, hypersthene and diallage, are well known to 
often possess a peculiar luster on cleavage surfaces due to the 
_ presence of inclusions, These are generally regarded as original 
in their nature, but Professor Judd considers them as secondary. 
He thinks that at great depths, under the action of pressure, cir- 
culating waters would have such an increased solvent effect that 
in certain planes a portion of the crystalline substance would be 
dissolved, leaving cavities of regular shape, resembling in their 
nature the “etched figures” which are produced in crystalline 
_ planes by the action of certain reagents. Into these cavities, or 
negative crystals, foreign matter is infiltrated, thus producing the 
so-called inclusions of indeterminable microlites. This process 
is designated as “ schillerization”’Messrs. Hague and Iddings 
contribute a most important paper on the development of crystal- 
lization in the igneous rocks of Washoe, Nevada,’ to which no 
Justice can be done here. Their main point is the convincing 
mass may solidify in a glassy form at the surface, and with a holo- 
_ Crystalline structure—even a coarsely crystalline structure—at 
_ greatdepths. The two forms are connected by every transitional 
2 Bulleti eS freer: S. lerap Ko. 8. 
y Journal uf the Geol. Soc., Aug., 1 
885. 
ger Survey, No. 17. Washington, 1885. 
