THE STRAIT OF SUNDA. 
" length of it with a hne of one hundred and fifty fathoms, 
" or nine hundred feet, without being able to reach the 
" bottom." How wonderful, how inconceivable, that such 
stupendous fabrics should rise into existence from the silent, 
but incessant and almost imperceptible, labours of such insig- 
nificant worms ! 
From the soft and leather-like consistence of the tubulated 
surfaces of the coral fabrics, it would appear that as the old 
animals die and their calcareous cells become rigid, succeed- 
ing generations continue their operations on the upper and 
lateral surfaces, each according to the particular form which 
nature has prescribed ; for the texture and construction of the 
rocks are very different in different parts of them ; and though 
they have received the general denomination of coral, few of 
them are of that description which, from their ramifications 
resembling the roots and branches of trees, led the ancient 
naturalists to conclude that they might form an inter- 
mediate class of organized beings, partaking of the double 
nature of plants and animals. It is true, the fragile branches 
of corals and corallines being easily broken, their materials 
may, by some process, be cemented together, and contribute 
to the formation of the amorphous bases of coral islands ; but 
the great masses of rock appear to be composed chiefly of 
madrepores, cellipores, and tubipores. In order to ascertain 
whether the central part, as well as the shore, of North 
Island consisted of these substances, we removed the soil, 
and at the depth of about three feet found large blocks of 
madrepores, and various cellular masses of calcareous forma- 
tion ; and, among other articles, Ave dug up a very large shell 
7 
