Fróðskaparrit - 01.01.1977, Síða 169

Glacial striae, roches moutonnees and ice movements
177
The west coast, which follows an approximately straight
line NW—SE, is mostly steep and inaccessible, while the east
coast is dissected by many deep inlets: Sandvík, Hvalbiar-
fjørður, Trongisvágur, Hovsfjørður and Vágsfjørður, which
continue inland as broad, gently rising valleys, all of them
except Hovsfjørður reaching almost to the west coast.
The dip on Suðuroy is generally north-easterly; on the
southerly part of the island it is to the ENE, while further
north it is to the NE and NNE. On the north-westerly part of
the island, in the area between Prestfjall and Grímsfjall, the
dip is northerly (N 5°). Sclorøder (1971) demonstrates geO-
physically the boundary between the lower and the middle
basalt series from here to the west. This boundary could imply
a more westerly dip in this area. Only the losVer and the
middle basalt series of the three mentioned above occur on
Suðuroy. They are separated by the coal-bearing sequence and
the tuff-agglomerate zone (fig. 1).
The lower basalt series is exposed on Hvalbiareiði and in
the valley south of Hvalba; north of Hvalba the middle basalt
series predominates. Similarly, the lower series is found in the
Trongisvág valley and over the entire island south of Oyrna-
fjall. Thus in the valley south of Hvalba, in the Trongisvág
valley and southwards, we find the valley type with broad
step-like valley sides, except in some areas where the strata are
thinner. The transition between the lower and the middle
basalt series is indicated by a vegetation-clad slope covering
the coal-bearing sequence and the tuff-agglomerate zone. The
convex landscape characteristic of the middle basalt series is
found on the northerly part of the island: Oyrnafjall, the area
between Trongisvágur and Hvalba, Grímsfjall, and the area
north of Hvalba.
The laminar zones on Suðuroy have, like the dikes, a pre-
dominantly NW—SE orientation, particularly in the southern
part of the island, i.e. in the lower basalt series. They are
usually broad, often strongly brecciated, and it is probable
that their formation antedates that of the middle basalt series