— M. Delesse on Globuliferous Rocks. 
and in the porphyries of l’Esterel and Oppenau, the silicious and 
feldspathic parts differ in color: and the distinctions of the two 
are often brought out in decomposition, the silicious part resisting 
change, while the feldspar ts kaolinised. Acids (especially 
hydrofluoric) develop the structure in a short time. 
The globules may be either solid throughout, or they may 
contain interior cavities: the former I call normal globules: the 
latter abnormal. 
independent crystals. 
The excess of silica in the feldspathic paste, is considered an 
excess of a solvent, as is admitted by M. Delafosse, for different 
silicates. 
Normal globules may either contain quartz or be free from it. 
Normal globules without quartz.—When globules of this 
kind have a crystalline structure, there are usually distinct 
cleavages. They are frequently observed in quartziferous, por- 
phyrites, or eurites. Figure 1 represents one of these globules 
ae 2 3. 
te. 
‘= 
a 
ee 
BE, 
b 
ey 
transparent, and it is surrounded by a thin milky or reddish 
compact zone of a feldspar which is probably triclinic. In cer- 
tain micaceous eurites of the Vosges (Minettes), the globules 
are spherical and consist of feldspathic lamell, probably of 
orthoclase, irregularly aggregated, along with some mica, and they 
have a reddish exterior like the above. When the structure is 
radiated, there is but a single system of rays, diverging from the 
centre; the radiation is often veryrude. At Oppenau, the feld- 
spar forms but a small part of the globule, it being surrounded 
by chalcedony. Yet it is evident that the globule has resulted 
from the tendency es to crystallize and to bring 
ica, te ae : 
the same influence, tes 
