THE FRESH- WATER LOCHS OF SCOTLAND. 27 



elevation being the same as that of Loch More. The basin is flat-bottomed 

 in character, more than half the lake-floor (or 54 per cent.) being covered 

 by over 5 feet of water. 



Loch Stack (see Plate IX.). Loch Stack lies about a mile to the 

 north-west of Loch More, the overflow from Loch More being carried 

 through Loch na h-Ealaidh, and by the short stream an Earachd, into 

 Loch Stack. Ben Stack, which rises steeply up from the south-western 

 shore of the loch, forms a striking object in the landscape. The loch 

 is very irregular in outline, having a fanciful resemblance to the capital 

 letter H, with one arm longer than the other; in fact, it may almost 

 be looked upon as two lochs joined by a shallow neck. The general 

 trend is north-west and south-east, the length of the longer arm being 

 over 2J miles, and that of the shorter arm nearly 1J miles, while a 

 line along the axis of maximum depth of one arm across the shallow 

 neck and along the axis of the other arm would be 3^ miles in length. 

 The waters of the loch cover an area of about 632 acres (or 1 square 

 mile), and the area draining into it directly is about 27^ square miles; 

 but since it receives the overflow from Lochs More and na h-Ealaidh, 

 the total drainage area is over 40 square miles. The maximum depth of 

 108 feet was observed in the wide portion of the longer arm, the maximum 

 depth recorded in the shorter arm being 85 feet. The volume of water 

 is estimated at about 988 million cubic feet, and the mean depth of the 

 whole loch at 36 feet. The loch was surveyed on September 6 and 8, 

 1902, the elevation of the lake-surface above the sea, as determined by 

 levelling from bench-mark, being 117'65 feet; this is almost identical 

 with the elevation determined by the officers of the Ordnance Survey on 

 September 23, 1870, viz. 117'5 feet. 



As already indicated, Loch Stack consists of two deep basins separated 

 from each other by shallow water. The deeper basin is contained in the 

 longer arm, the maximum depth of 108 feet being recorded about a mile 

 from the southern end, and about 1J miles from the northern end, of that 

 arm. This was the only sounding taken in depths exceeding 100 feet, 

 and here there is a 7 5 -feet area three-quarters of a mile in length, and a 

 50-feet area over a mile in length. Near the northern end of this arm 

 there is a small, isolated 50-feet area, based on soundings in 50 and 

 63 feet, separated from the main 50-feet area by a shoaling of the water 

 at the narrow constriction in the outline of the loch, about half a mile 

 from the northern end, where the depth is less than 30 feet. The shallower 

 basin in the shorter arm of the loch is regular in conformation, the 50-feet 

 area being about three-quarters of a mile in length, and enclosing a 75-feet 

 area a quarter of a mile in length, based on soundings in 77, 81, and 

 85 feet. The last-mentioned sounding was recorded about a quarter of 

 a mile from the eastern shore. In the shallow neck joining the two arms 

 of the loch, the deepest sounding recorded was in 16 feet. In one or two 



