20, 3 Schenck: Physiography and Geology of Samar 245 
In general these beds southeast of Catbalogan dip to the 
northwest and strike northeast, but show considerable variation 
in both dip and strike within short distances, thus evidencing 
faulting. Apparently these beds, like those on the beach north 
of the town, are post-Vigo, and, by their nature point to an un- 
conformity between the Pliocene and the Miocene. 
Gandara River.——From Catbalogan the party went to Calba- 
yog and then up Gandara River to Matuguinao. Before going 
. up the river, however, we spent a day or so in the vicinity of 
Calbayog, where we found that the hills southeast of Oquendo, 
north of Calbayog, present fairly abundant outcrops of lignitic 
sandstone, one specimen of which is a soft, fine-grained, noncal- 
careous, friable, buff sandstone. The traverse from Buao to 
Matuguinao disclosed flat, or nearly flat, outcrops of sandy 
clay-shale, or marl; while on the trip down the river, we saw 
evidence, though insufficient, of a westward-sloping monocline, 
which at places is possibly folded into minor shallow synclines 
and gentle anticlines, and at places is faulted. The majority 
of the strikes were northwest. The river in its upper reaches 
near Matuguinao meanders to a remarkable extent, but cuts 
through no limestone, although that formation is found at 
locality F877 near Matuguinao. This is a hard, white Miocene 
limestone containing Lepidocyclina and Lithothamnium. 
Northeast of this interior barrio, at an elevation of about 
400 meters, lying in close association with limestone, is a com- 
pact, brown-weathering, blue sandstone, medium-grained, cal- 
careous, and consisting of angular to rounded grains, some of 
which are feldspar, quartz, and magnetite. It might be called 
a calcareous tuff. 
Cross-island traverse—The cross-island traverse did not 
disclose sufficient evidence to warrant any exact statement con- 
cerning stratigraphy or structure. It did indicate, however, 
that there is an igneous core to the island, and we were led 
strongly to suspect the existence of a basal igneous complex or 
& basement complex of metamorphics. This traverse is shown 
in Plate 4 with an explanation of the geological features. From 
these data an effort was made to construct a profile that would 
show, at a glance, the structure of the island; but it was found 
that the information at hand was insufficient to complete the 
Picture, and the attempt was abandoned. I am led to the be- 
lief that the central portion of the island is composed, principal- 
ly, of flat-lying beds of marl and sandstone of possible Pleisto- 
cene age and great masses of Miocene and Pliocene limestones 
