RED SEA. 
205 
the most singular shapes, rise from this bank. Many of 
them may have been formed by the growth of coral on 
small abraded islets ; but some almost atoll-formed reefs 
rising from deep water near a promontory in lat. 24°, are 
probably allied to the barrier class. I have not, however, 
ventured to colour this portion of coast blue . — On the west 
coast, from lat. 19° to 17° (south of the space coloured blue 
on the map), there are many low islets of small dimensions 
not much elongated, and rising out of great depths at a 
distance from the coast : these cannot be classed either 
with atolls, or barrier, or fringing-reefs. 
Eastern Coast . — There are many small outlying coral- 
reefs along this whole line of coast ; but as the greater 
number rise from banks not very deeply submerged, their 
origin, as we have seen, may be due simply to the growth 
of corals on an irregular abraded foundation. But between 
lat. 18° and 20° there are so many linear, elliptic and ex- 
tremely small reefs, rising abruptly out of profound depths, 
that the same reasons which led me to colour a portion of 
the west coast blue, have induced me here to do the same. 
There are some small outlying reefs on the east coast, north 
of lat. 20° (the northern limit coloured blue), which rise 
from deep water ; but as they are not numerous, and as 
scarcely any of them are linear, I have left them un- 
coloured. 
In the southern parts of the Bed Sea, considerable 
spaces of the main land, and some of the Dlialac islands, 
are skirted by reefs, which, as I am informed by Captain 
Moresby, are of living coral, and have all the characters of 
the fringing class. As there are here no outlying linear 
or sickle-formed reefs, rising out of unfathomable depths, 
I have coloured these parts of the coast red. On similar 
grounds I have coloured the northern parts of the western 
coast (north of lat. 24° 30') red, and likewise the shores of 
