44 WIENS OULNAL OR GROELO GN: 
specimens examined come from the railroad cutting near the 
hamlet of Kolautziki. A short petrographical description by 
Dr. R. Lepsius, which will be referred to later, will be found on 
page 604 of Philippson’s ‘‘ Peloponnes.”’ 
The specimens show a fine-grained, but not very compact, 
very light gray or light brown groundmass which contains many 
minute black biotite flakes and feldspar and quartz grains. In 
this are thickly scattered larger phenocrysts of colorless feldspar, 
small biotite tables and grains or bi-pyramids of pink or ame- 
thystine quartz, which on the weathered surfaces have entirely 
lost their color. These crystals do not show much definite 
arrangement in lines of flow. 
Under the microscope they show a highly vitreous ground- 
mass traversed by numerous perlitic cracks, and containing few 
microlites, but flow streaks of brown or greenish dusty matter. In 
the groundmass also lie many small flakes of olive-green biotite, 
with some small plagioclases and still fewer small quartz grains 
which are arranged in lines of flow. Hardly any maynetite is 
present. 
The phenocrysts are of biotite, quartz, and feldspar. The 
first are not very large hexagonal tables, olive-green when fresh, 
but banded or mottled with reddish brown in the decomposed 
specimens. They are very poor in inclusions, only a few plagio- 
clases and zircons being thus met with. Clear, colorless quartz 
grains are common, generally with rounded outlines, though 
occasionally showing crystallographic boundaries. They are 
quite free from inclusions, no glass being noted and only a few 
colorless zircons. 
The feldspar phenocrysts which contain few inclusions of 
glass, biotite, and zircon in almost every case are plagioclase, 
though many of them are simple crystals, and twinning lamelle 
are rare, one case giving angles which indicate labradorite. 
Though Lepsius makes the prevailing feldspar out to be sani- 
dine, and hence calls the rock a ‘quartz trachyte,” my own 
observations fail to confirm this. Though the crystals are gen- 
erally simple and clear and hence look like sanidine, careful 
