GEOLOGY: W. G. FOYE 
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out to the eastward. The whole circumference of the inland is marked 
by pocket harbors and jutting headlands. 
Along the southern and eastern sides of the island a rough country of 
volcanic hills extends 6 or 8 miles inland. The principal divides are 
found in these hills. The larger rivers run north and northwest across 
elevated plains 200 to 300 feet high before forming flood-plains along 
the northern coast. 
The geological history of the island is not so complex as that of Viti 
Levu. The fundamental rocks of the island are not exposed, to the 
writer's knowledge. Their character is, therefore, problematic. Into 
these rocks were intruded bathoKthic masses which solidified to form 
gabbro. The old land was then greatly eroded and the plutonic rocks 
were exposed. Later the island subsided. During the erosion and sub- 
sidence volcanic intrusions mantled the irregular land surface uncon- 
formably with a cover of acid andesites and rhyolites. 
The island remained submerged throughout the period of sedimenta- 
tion and folding in which the folded sediments of Viti Levu were devel- 
oped. Submarine volcanoes were active and 2000 to 3000 feet of 
ash and agglomerate, largely composed of hyper sthene andesite, were 
conformably laid down on the submerged surface. At the time of the 
upHft of the coastal series of Vitu Levu, Vanua Levu was elevated into 
an island form, The movements were accompanied by faulting and 
tilting and have continued to the present. 
The period of upHft has been complicated by downward movements 
from time to time which may best be studied near Lambasa on the north- 
ern coast. During a still-stand a local peneplain was developed far into 
the interior which now is found at an elevation of 50 to 200 feet. The 
island was later uplifted and the peneplain just described was carved into 
sub-mature hills near the coast. A period of submergence followed 
during which coraliferous limestones were deposited about the spur-ends 
of the coastal hills. The region was then elevated and the limestones 
are now found from 50 to 100 feet above the sea. A recent submergence 
has allowed volcanic silts, brought down by the rivers, to fill up valleys 
eroded in the limestone. Since the uplift a series of basaltic eruptions 
have scattered their debris over the surface of the island but at a period 
so remote that the basaltic cones are now eroded to sub -maturity. 
Elevated coral reefs are known from but one place along the northern 
coast. They occur at an elevation of 75 feet, just west of Lambasa. 
They are found within the bay separating the main island from the 
eastern peninsula^, but are not known to occur on the peninsula itself. 
Reefs have very recently been elevated along the southeastern coast 
