174 
CORAL ISLANDS. 
where the tide reaches every day, it is found to be 
full of polypi of different lengths and colours ; some 
being as fine as a thread, of a bright yellow, and 
sometimes of a blue colour. The growth of coral 
appears to cease when the worm is no longer ex- 
posed to the washing of the sea. Thus a reef rises 
in the form of a cauliflower, till the top has gained 
the level of the highest tides, above which the ani- 
malcules have no power to advance, and the reef, of 
course, no longer extends upward." 
We shall conclude our remarks on the formation 
of coral rocks with the following extract from the 
" Pelican Island," a poem by James Montgomery. 
" I saw the living pile ascend, 
The mausoleum of its architects, 
Still dying upward as their labours closed ; 
Slime the material, but the slime was turned 
To adamant by their petrific touch. 
Frail were their frames, ephemeral their lives, 
Their masonry imperishable. All 
Life's needful functions, food, exertion, rest, 
By nice economy of Providence, 
Were overruled, to carry on the process 
Which out of water brought forth solid rock. 
Atom by atom, thus the mountain grew 
A coral island, stretching east and west ; 
Steep were the flanks, with precipices sharp, 
Descending to their base in ocean gloom. 
Chasms few, and narrow, and irregular, 
Formed harbours safe at once and perilous ; 
Safe for defence, but perilous to enter. 
A sea-lake shone amid the fossil isle, 
Reflecting in a ring its cliffs and caverns, 
With heaven itself seen like a lake below.'* 
