20, 3 Schenck: Physiography and Geology of Samar 255 
and from the nature of these earlier formations one would not 
expect to find the Vigo and later sandstones anything but the 
predominantly feldspathic rocks that they are. The interesting 
feature of this rock, Moody states, is that it is here interbedded 
with a green shale. This is a slightly calcareous, fine-grained 
rock, which resembles a jointed clay. No fossils were noted 
in it. 
Balicuatro Point, as observed from a launch, probably is 
formed of basalt, in part, since the rocks forming it appeared 
to have the color of that rock and at one place seemed to exhibit 
characteristic columns of basalt. 
Basey to Calbiga and Catbalogan.—The final trip was by 
launch from Basey to Catbalogan, via Calbiga. A specimen of 
compact, clean white, foraminiferal limestone, probably Miocene 
in age, was collected from the seacoast at the sitio of Hilaba, 
municipality of Basey. This rock is quite free from detrital 
impurities. 
The prominent hill southwest of Basey, southern coast of 
Samar, is made up in part of conglomerate, a speckled gray, 
somewhat calcareous, coarse rock in which pebbles of an igneous 
character, slate, secondary quartz, and fragments of magnetite 
are distinguishable. The pebbles average less than 1 centimeter 
in diameter. This conglomerate overlies faulted sandstones and 
shales of possible Vigo age. It probably is a purely local con- 
glomerate. 
In passing through San Juanico Strait, sedimentary beds are 
seen on each side, though some igneous rocks occur. There is 
only one rock from Samar in the Bureau of Science collection 
that was not collected by our party, and this specimen is one 
that dates from the Spanish régime. It is labeled “traquita 
anfibolifera” (amphibole trachyte) and is from visita Nabatas, 
municipality of Villareal, south of Talalora, at the northern end 
of San Juanico Strait. This rock is dark gray, fine-grained, and 
compact. Thin sections show that the principal phenocrysts are 
hornblende and glassy feldspars, though some augite is present, 
as well as grains of magnetite. The groundmass is made up 
chiefly of minute crystals of feldspars of another generation 
than the larger feldspar phenocrysts. This trachyte is similar 
to a hornblende-andesite from Caibiran on the east coast of 
Biliran Island. 
A noncaleareous clastic rock outcrops at Cologdog Point, near 
the northern entrance of this channel, and near the town of 
Talalora. The rock is very fine-grained, compact, buff sand- 
