PERSIAN GULF. 
259 
drifting of sediment or subterranean movements, produced 
the headlands, likewise produced, as might have been ex- 
pected, submarine prolongations to them ; and these to- 
wards their outer extremities have since afforded a favour- 
able basis for the growth of coral-reefs, and subsequently for 
the formation of islets. As these reefs clearly belong to the 
fringing class, the Querimba Islands have been coloured 
red. — Monabila (13° 32' S.) : in the plan of this harbour, 
the headlands outside are fringed by reefs apparently of 
coral; coloured red. — Mozambique { 15° S.) : the outer part 
of the island on which the city is built, and the neighbour- 
ing islands are fringed by coral-reefs ; coloured red. 
From the description given in Owen’s Nar. (vol. i. p. 162) 
the shore from Mozambique to Delagoa Bay appears to be 
low and sandy : many of the shoals and islets off this line 
of coast are of coral formation ; but from their small size 
and lowness, it is not possible, from the charts, to know 
whether they are truly fringed. Hence this portion of 
coast is left uncoloured, as are likewise those parts more 
northward, of which no mention has been made in the 
foregoing pages, from the want of information. 1 
Pebsian Gulf. — From the charts lately published on a 
large scale by the East Indian Company, it appears that 
several parts, especially the southern shores, are fringed by 
coral-reefs ; but as the water is very shallow, and as there 
are numerous sand-banks, which are difficult to distin- 
1 [The whole of the eastern coast of Africa, from the equator to 
Mozambique (at least) is of upraised coral, and so are the outlying 
islands. Fringing-reefs occur everywhere, partly formed by the 
action of the sea wearing back the upraised coral, and partly by 
living coral. In Zanzibar undoubted coralline limestone exists at 
100 feet, and a limestone of origin as yet undetermined at 300 feet. 
— W. From Wasin to Pangani (about lat. 5° S.) there is a barrier of 
large coral-reefs from 2 to 5 miles off shore with a deep channel inside, 
sometimes as much as 20 fathoms in depth. — Lieut. Chas. Smith.— 
From Mr. Darwin’s papers.] 
