THE FRESH- WATER LOCHS OF SCOTLAND. 215 



(2) The Slattadale basiu. 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 Mor 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 2^ 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 Mor 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 Mor to the mouth of 

 Allt na Doire is very marked. The lowest part of the ridge is 83 feet 



