With no explanation, label each line with "O", "location-bodiesofwater", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
The
oldest
rock
units
recognized
in
the
west
of
the
country
,
along
the
Gambia
River
are
sandstones
and
kaolinitic
claystones
from
the
Oligocene
,
Miocene
or
Pliocene
.
The:O
oldest:O
rock:O
units:O
recognized:O
in:O
the:O
west:O
of:O
the:O
country:O
,:O
along:O
the:O
Gambia:location-bodiesofwater
River:location-bodiesofwater
are:O
sandstones:O
and:O
kaolinitic:O
claystones:O
from:O
the:O
Oligocene:O
,:O
Miocene:O
or:O
Pliocene:O
.:O