266 BATHYMETRICAL SURVEY OF 



Geal Loch (see Plate OXXIV.) is a small simple basin lying at the head 

 of Loch Lomond, into which it drains. It is one-third of a mile in length 

 in a north and south direction, and covers an area of about 28 acres. The 

 maximum depth of 23 feet was recorded towards the northern end, the 

 mean depth being estimated at nearly 10^ feet, and the volume of water at 

 12 million cubic feet. 



Loch Sloy (see Plate CXXIV.) is situated about 3 miles south-west from 

 Ardlui, and about 2 miles to the west of the upper part of Loch Lomond, 

 the mighty Ben Vorlich rising between them ; while to the west of Loch 

 Sloy rises Beinn Dubh, and to the south-west Ben Voine and other lofty 

 peaks. The floor of the loch is rocky, and the hollow in which it rests has 

 probably been filled up to a large extent by boulders fallen from the steep 

 slopes of Ben Vorlich and Beinn Dubh ; the outflowing stream flows over 

 solid rock, and the bed of the loch is undoubtedly a rock basin. The loch 

 trends from north-west to south-east, and is extremely elongate in outline, 

 being over a mile in length, but only one-eighth of a mile in maximum 

 breadth. The superficial area is about 65 acres, of which about 73 per 

 cent, is covered by less than 10 feet of water, and the drainage area is 

 extensive, exceeding 6 square miles. The maximum depth of 31 feet was 

 recorded near the southern end, the mean depth being estimated at over 

 8 feet, and the volume at 23 million cubic feet. The floor of the loch is 

 irregular, there being two 10-feet basins, the larger, over half a mile in 

 length, occupying the southern portion of the loch, separated from the 

 smaller, a quarter of a mile in length, by a ridge covered by 1 and 2 feet 

 of water. The loch was surveyed on June 11, 1903, but the elevation 

 above the sea could not be determined ; judging from spot-levels it 

 appears to be about 810 feet above sea-level. 



Kilbirnie Loch (see Plate OXXXII.) is a broad oblong sheet of water in 

 the county of Ayr, between the villages of Kilbirnie and Beith, 16 miles 

 from Glasgow. It lies entirely in cultivated land, the G. and S.W. Eailway 

 skirts its eastern shore, and the southern end is occupied by ironworks 

 and chemical works, the debris from which encroaches upon the loch. The 

 length is over l miles, and the greatest breadth is fully one-third of a mile. 

 The loch is shallow, more than half the area being covered by less than 

 10 feet of water, and the mean depth is 9J feet. The west side is shallow, 

 a depression running parallel to the east shore, in which there are two 

 holes of 24 feet and 30 feet respectively. The area is about 247 acres, or 

 nearly two-fifths of a square mile, and the volume of water 105 millions of 

 cubic feet. The drainage area extends to about 2 square miles. The Maich 

 burn is the chief feeder, entering at the north end. The outflow is by the 

 Dubb's burn, which flows from the north-east corner of the loch northward 

 by the bed of the Barr Loch (now drained) into Castle Semple Loch. 



On the date of the survey (July 26, 1906) the surface was 100'3 feet 

 above sea-level. 



