are composed
of a number of isolated, scattered islands, while the Central group
forms a chain, which divides at Epi into an eastern and a western
branch, and encloses a stretch of sea, hemming it in on all sides
except the north. On the coast of this inland sea, especially on the
western islands, large coral formations have grown, changing what was
originally narrow mountain chains, running north and south, to larger
islands. Indeed, most of them seem to consist of a volcanic nucleus,
on which lie great coral banks, often 200 m. high; these usually
drop in five steep steps to the sea, and then merge into the living
coral-reef in the water. Most of the islands, therefore, appear as
typical table-islands, out of which, in the largest ones, rise the
rounded tops of the volcanic stones. They are all very mountainous;
the highest point is Santo Peak, 1500 m. high.

The tides cause very nasty tide-rips in the narrow channels between
the islands of the Central group; but inside, the sea is fairly good,
and the reefs offer plenty of anchorage for small craft. Much less
safe are the open archipelagoes of the Banks and Torres Islands and
of the Southern New Hebrides, where the swell of the open ocean is
unbroken by any land and harbours are scarce.

There are three active volcanoes on the New Hebrides--the mighty
double crater on Ambrym, the steep cone of Lopevi, and the volcano
of Tanna. There is a half-extinct volcano on Venua Lava, and many
other islands show distinct traces of former volcanic activity,
such as Meralava and Ureparapara, one side of which has broken down,
so that now there is a smooth bay where once the lava boiled.

Rivers are found only on the larger islands, where there are volcanic
rocks. In the coral rocks the rain-water oozes rapidly away, so
that fresh-water springs are not frequently found, in spite of very
considerable rainfall.

Climate

The climate is not hot and very equable. The average temperature in
Efate in 1910 was 24.335 deg. C.; the hottest month was February, with
an average of 27.295 deg., the coolest, July with 11.9 deg. C. The lowest
absolute temperature was 11.9 deg. C. in August, and the highest 35.6 deg.
C. in March. The average yearly variation, therefore, was 5.48 deg.,
and the absolute difference 23.7 deg..

The rainfall is very heavy. In December the maximum, 564 mm., was
reached, and in June the minimum, 22 mm. The total rainfall was 3.012
mm., giving a daily average