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Lawn Hill.

At Lawn hill, on the east coast of Graham island, black,
dense, fluidal basalts, some of them with well developed colum-
nar structures, are exposed on the shore. One outcrop of these
rocks is seamed with several calcite veins filling joint cracks,
which also contain tar. The veins are usually less than an inch
wide and many of them are as thin as paper; they are filled with
white and yellowish calcite, more rarely with quartz, and exhibit
comb-structure, often with a channel in the middle of the vein.
Black tarry matter exudes from the veins on warm days when the
rocks are heated by the sun. The tar is odourless and sticky,
and slightly softer than is pitch under ordinary summer temper-
atures. The fact that the supply of tar does not seem to dimin-
ish, and has been continuous for some years at least, indicates
that it is supplied from a natural source below. Apparently
exposure to the air hardens the tar; for the material beneath the
surface, although at a considerably lower temperature (that of
the enclosing rocks) than that of the atmosphere, is sufficiently
fluid to travel through the cracks. The total amount of tar is
small, and the quantity exuding from the cracks is dependent
on the amount of sunshine.

In some of the loose basaltic agglomerates which in part
form the eminence called Lawn hill, irregular patches contain
similar black tar in the interstices of the rock. This tar doubtless
is from the same source as that exuding on the beach.

On the ranch of Edgar Ashton, about 2 miles inland from
the occurrences noted above, similar tar is reported to have been
found within a few feet of the surface of the ground, in a grey
soft clay.

Tian Point.

Black tar like that described above is found at several
localities on the west coast of Graham island, notably at Frederick
island, Tian point, and Otard bay. At Frederick island films of
tar are found in the flaggy argillites of the Maude formation, a
type of deposit which has been already described.

The occurrence at Tian point (to which that at Otard bay