THE FRESH-WATER LOCHS OF SCOTLAND. 
215 
(2) The Slattadale basin. — This basin extends from west of Eilean 
Ruairid Mor to south of Eilean Subhainn. The 150-feet area has a 
length of 2 miles and a mean breadth of a quarter of a mile. The curve 
traced out by this contour to the east of the Slattadale river is very 
remarkable ; the extension of the shallower part of the loch into the 
150-feet area is in the direction of the Slattadale river, but the sound- 
ings nearer to the shore give no indication that this bank is due to the 
material brought down by the river. The 200-feet area extends from 
south of Eilean Ruairid Mbr to north of Stalla nam Manach, its length 
being nearly 1^ miles, and its average breadth about 150 yards. The 
greatest depth is 232 feet in the extreme north-west of the basin. In 
a line with the curious indentation in the 150-feet contour-line the 
200-feet basin is very narrow and shallow (202 feet). 
Comparatively deep soundings were obtained in all the channels 
extending into the islands, and it is noteworthy that the long and 
narrow passage between Eilean Subhainn and Garbh Eilean lies in 
a line with the narrow prolongation of deeper water from Rudha 
Chailleach into the shallow water north of the islands. 
Ob na h-Innse Moire in Eilean Subhainn was cut off from the main 
part of the loch by a sand-bar. This was also the case with the inlet to 
the north-west of Ob na h-Innse Moire, but this inlet had its surface 
covered with weeds and boulders. 
(3) The Ardlair basin. — The outline of this basin is also very 
irregular, and the bottom more so than in either of the other basins. 
The 100-feet area has a length of 3J miles and a mean breadth of 
three-quarters of a mile. The 200-feet area has a length of 2J miles and 
an average breadth of one-third of a mile. The length of the 250-feet 
basin is two-thirds of a mile and the average breadth a quarter of a 
mile. The greatest depth in this basin is 285 feet, occurring about 
700 yards to the south-east of Rudh’ Aird an Anail. 
In this basin the contour-lines run very close to the north-eastern 
shore in the western and central parts of the basin, but spread out 
towards the eastern part. Again, they run very close to the shore 
round the western coast of Eilean Ruairid Mbr and round Rudh’ Aird 
an Anail. They have a very sinuous outline in the eastern part of the 
basin. 
As stated above, the floor of this basin is very irregular; several 
small hills rise above the general level of the bottom, as that to the 
south of Ardlair and that to the east of Rudh' Aird an Anail. The 
north-western extension of this basin, called River Ewe,^' has 
already been noticed. 
There remain for consideration the ridges between the basins and 
the large tract of shallow water to the north of the islands. The 
ridge which runs across from Eilean Ruairid Mbr to the mouth of 
Allt na Doire is very marked. The lowest part of the ridge is 83 feet 
