File:The Quarterly journal of the Geological Society of London (12736294595).jpg

678
R. L. JACK AND J. HORNE ON GLACIAL DRIFT
about 5 miles above Szigeth, the main road ascends to the level of
the upper terrace, which sweeps south to the base of the hills. At
this point the valley is only about a mile and a half broad, and
seems to be filled entirely with alluvial deposits. The same fact is
observable at Gross Bocsko, where the valley narrows to not much
more than a quarter of a mile. Again, near Lonka, several excellent
sections of these alluvial gravels are met with, which likewise
stretch from the one hill-slope to the other. At this point there are
also two well-marked terraces ; the gravel of the upper terrace
being upwards of 20 feet thick. The same horizontal beddiug is
discernible, while the deposit, as a whole, is pretty coarse, many
of the stones measuring 2 feet across. Here the Flysch-beds are
seen dipping up stream at an angle of 20°, and within a short dis-
tance reversed at a high angle, as shown in the following section
(fig. 2).
Fig. 2. — Section near Lonka.
a. Old alluvial terrace.
b. Kecent alluvium.
Sandstones and shales. Flysch-
beds thrown into a synclinal fold.
Bather more than a mile beyond Lonka, the river flows between
steep pine-clad hills with no alluvial or drift-deposits on either
bank. Near this, however, three large erratics of quartz rock were
observed, one of which measured upwards of 90 cubic feet, and
another (partly concealed) upwards of 10 feet in length. Higher
up the valley, in a roadside-cutting, the quartz rock is seen in place,
and is rapidly succeeded by a fine-grained blue limestone, the latter
probably belonging to the patch of Dyas or Permian rocks repre-
sented in Yon Hauer's map. On the right bank of the Theiss, just
about a mile and a half below the point where it receives the waters
of the Visso, another drift-section is exposed. It occurs on the road-
side, and is about 100 feet above the level of the river. The
deposit consists of stiff dark-blue clay, stuck full of stones, some of
which range up to 8 cubic feet. The blocks, as a rule, are not
rounded ; and, though a careful search was made, no instances of
striae were observed. The absence of such may be accounted for by
the fact that the stones consist mainly of soft brownish- grey
micaceous sandstones, which would not readily retain glacial
markings. This section is about 2050 feet above the sea-level, by
aneroid measurement.