Sect. II. 
EATE OF GEOWTH. 
105 
apart on a sand-bank three feet deep at low u-ater. 
Each portion weighed ten pounds, and was kept in 
its place by stakes. Similar quantities were placed 
in a clump and secured as the rest. This was done 
in December 1830. In July following, each detached 
mass was nearly level with the sea at low water, quite 
immovable, and several feet long, stretching, like the 
parent reef, in the line of the coast-current from north 
to south. The masses accumulated in a clump were 
found equally increased, but some of the species in 
such unequal ratios as to be growing over each other.’ 1 
The loss of Dr. Allan’s magnificent collection by 
shipwreck, unfortunately prevents its being known 
to what genera these corals belonged ; but from the 
numbers experimented on, it is certain that all the 
more conspicuous kinds must have been included. 
Dr. Allan informs me, in a letter, that he believes 
it was a Madrepora which grew most vigorously. 
One may be permitted to suspect that the level of the 
sea might possibly have been somewhat different at the 
two stated periods; nevertheless, it is quite evident 
that the growth of the ten-pound masses, during the 
six or seven months at the end of which they were 
found to be immovably fixed 2 and several feet in 
length, must have been very great. The fact of the 
1 I owe the above extract to the kindness of Dr. Malcolmson. 
2 It is stated by Mr. De la Beche (Geological Manual, p. 143), on 
the authority of Mr. Lloyd, who surveyed the Isthmus of Panama, 
that some specimens of Polypifers, placed by him in a sheltered 
pool of water, were found in the course of a few days firmly fixed by 
the secretion of a stony matter, to the bottom. 
