88 
CONDITIONS FAVOURABLE TO 
Ch. IV. 
the living polypifers, appears at first sight probable ; 
and in sounding off Keeling atoll and Mauritius, the 
arming of the lead invariably came up clean, where 
the coral was growing vigorously. A strange belief, 
which, according to Captain Owen , 1 is general amongst 
the inhabitants of the Maldiva atolls, namely, that 
corals have roots, and therefore grow up again if 
merely broken down to the surface, but if rooted 
out, are permanently destroyed, — I am inclined to 
believe arises from the fact that loose sand injures 
the polypifers. For it is probable that sand would 
accumulate in the hollows formed by tearing out the 
corals, but not on the broken and projecting stumps ; 
and therefore, in the former case, the fresh growth 
of the coral would be prevented. By this means 
the inhabitants keep their harbours clear ; and thus 
the French governor of St. Mary’s, in Madagascar, 
‘ cleared out and made a beautiful little port at that 
place.’ 
In the last chapter I remarked, that fringing- 
reefs are almost universally breached where streams 
enter the sea . 2 Most authors have attributed this fact 
to the injurious effects of the fresh water, even where 
1 Captain Owen on the Geography of the Maldiva Islands, Geo- 
graph. Journal, vol. ii. p. 88. 
2 Lieut. Wellstead and others have remarked that this is the case 
in the Red Sea : Dr. Riippell (Reise, in Abyss. Band. i. s. 142) says 
that there are pear-shaped harbours in the upraised coral-coast, into 
which periodical streams enter. From this circumstance, I presume, 
we must infer that, before the upheaval of the strata now forming 
the coast-land, fresh water and sediment entered the sea at these 
points ; and the coral being thus prevented growing, the pear-shaped 
harbours were produced. 
