NORTH MAHLOS BANK. 161 
of a rocky shore, as the beach south and east is clothed with sandstone. At the east end 
this runs out into four ridges, two dipping to the north and two to the south, showing 
periods of rest while the land was being washed away. The method of erosion is plain to 
the south, where the waves have undermined the rock for 3 or 4 feet. The sea washes 
up under the masses at low tide with each wave, and has further in many places eaten 
through the rock above, forming blow-holes which spout after every breaker. A block finally 
gets broken off, and then is quickly removed. The other sides of the island show loss in 
fallen coconuts and other timber, and, indeed, the whole island is slowly disappearing now 
that it has lost its protecting rocks. 
Inguradu is intermediate to Fainu and Kenurus, having a small rocky island to the 
north-east, connected by a ridge of rocks to the main island. The reef off the smaller 
island is only about 20 yards broad, but off the east end of the main island it is 80 to 
100 yards. The beach above it is for the most part covered with loose masses of rock, 
piled up for a height of 9 to 10 feet above the reef-flat, which itself is covered with 
pinnacles and masses of the rock. The latter extend round the north and south sides of 
the island on the reef, and connect with a series of similar rocks in one part of the beach of 
the west end, which is evidently now washing away. The original reef before elevation would 
hence appear to have been nearly circular, perhaps partially filled in in the centre with sand. 
Indeed every island of the east rim appears to have had at one time a fringe of rocks 
round its east end, which fringe has been or is now being eroded away. The topography 
of the present islands depends on how far this fringe continued round on their north and 
south reefs and on the extent of its erosion in each case. The sandy area behind it was 
apparently due in some to an elevated sand-flat, but principally to the protection it afforded 
so as to allow the heaping up of sand by the wind and waves, As a general rule the 
breadth of the rocky area to the east did not exceed 150 yards, narrowing westwards both 
along the north and south sides of the reef. Its extensions did not usually meet one 
another on the west end of the reef, but it has been seen in Inguradu that they closely 
approached one another. Hurudu (fig. 28) shows a 
step further, a chart made by Mr Forster Cooper, 
showing that the island was completely encircled by 
coral rock. The island before elevation was an almost 
flat reef at the low tide level—the west end slhghtly 
lower—700 yards in diameter with a pool of water 
of about 4 feet deep in the centre. On elevation the 
rock began to be washed away on all sides except 
the west, where some sand was heaped up. In 
the latter position trees began to grow on the sand, 
but the sand itself has now been largely removed, 
and the rock crops out in the base of the beach and “u, ; 
forms a line in the land 20 to 60 yards further back. eye Dhan, rer 
Along the south and south-east sides a coarse beach- F128. Hurndu Island. The rocky area of the 
rock also has formed of coral and fragments out of ORR CU IEE Ta) GIGI ab MEE OE 
4 ita te & coarse coral rock at base of beach. B. Sand 
the limestone, joimed together by carbonate of lime area. (From a sketch-map made by Mr Forster 
deposited from the sea-water. Wahdu and Bernam Cooper.) 
are now the only reefs on the east side of the bank 
that are definite faro (small atolls with lagoons or velu). ‘The former has a rocky island 
Ze, 

