154 J. STANLEY GARDINER. 
between the atolls. Haddumati to the south and Makunudu to the north-west may arise 
separately, but Ihavandifolu is almost certainly founded on the same bank, the single 
sounding, 601 fathoms, in the channel between it and Tiladumati lying considerably to the 
east of the narrowest part of the passage. The various banks, then, arise as so many 
plateaus from a common plateau, which has a general depth of about 200 fathoms. This 
plateau presumably includes on its surface all the banks between Kolumadulu and Ihavandifolu. 
It probably continues at about the same depth beneath the various banks, to seaward passing 
into the general slope off the reefs. In the channels, however, as soundings between the 
two Male atolls show, the depth increases gradually to seaward between the various banks. 
In sounding we used the 28 lb. “ Valve” leads of Admiralty pattern and the “Snapper,” 
as made by the Telegraphic Construction and Maintenance Co. of Silvertown. The former 
leads failed on the great plateau to bring up samples of the bottom, and those procured 
by means of the “Snapper” were very meagre. In the passages between the banks the 
bottom was evidently extremely hard, only an occasional piece of dead coral being obtained. 
In the sections across the plateau it was generally similar, with, in places, very coarse sand 
of broken coral and shell fragments. Fine mud was obtained in the soundings of 205 fathoms 
due west of South Male, its deposition here being due probably to the protection afforded 
by that atoll to the east and Ari to the west. The behaviour of the lead in sounding 
especially in the channels left no doubt but that the current found on the surface extended 
to the bottom with at least as great force’. 
The banks have to seaward the regular characteristic platform, extending out from the 
reefs for a distance usually of about 300 yards with a gradual slope to 40 or 50 fathoms. 
This is followed by the “steep,” which at about 150 fathoms passes into a more gradual 
slope, perhaps the original slope of the whole plateau. This depth though appeared to be 
very irregular even in a small area, off the south-east of North Male and the north-east 
of South Male varying between 120 and 180 fathoms. Off North Mahlos, however, the line 
seemed more regular, lying in three places between 140 and 150 fathoms. Towards the 
central basin of the plateau the reef-platform is much narrower, seldom exceeding 200 yards 
in breadth. The steep commences generally below 30 fathoms and the fall then is absolutely 
precipitous to at least 110 fathoms, the lead not resting anywhere. Of course over such 
an enormous area the variation in slope may be very large, but the platform appeared to 
be distinctly narrower and the steep more precipitous against the central basin. In the 
channels between the banks the platform is usually intermediate in breadth, but the steep 
commences at a shallower depth than on either side, and is almost perpendicular. In 
entering North Nilandu from the south the sounding machine near the stern of the ss. 
“Tleafaee” recorded 118 fathoms, while the bottom could be seen over the bows of the 
vessel, a distance of less than 100 feet (fig. 26,0). In the Maimbudu passage of South 
Nilandu also the lead gave 162 fathoms, but when we had got in about 50 fathoms of 
wire the bows of the steamer drifted over a 6-fathom patch; the lead at the same time 
stuck in something on the slope and was lost (fig. 26, B). Off the south-east of Ami, east 
of Dungatee the lead hung for a moment at 32 fathoms, and then fell off to 114 fathoms, 
a fresh sounding a few yards further out giving 126 fathoms. The inner sides of all these 
atolls may be considered to be their leeward sides, as the force of the waves and currents 
1 When we were sounding in April, the currents were invariably setting from east to west, the wind being from 
the west, and hence opposed to them. 
