THE FRESH-WATER LOCHS OF SCOTLAND. 93 



nearly in the broadest part. It is of small extent (a quarter of a mile 

 long), and has a greatest depth of 58 feet. At the date of the eurvey 

 (July 10 and 11, 1903) the surface was 673'3 feet above sea-level. This 

 was considerably higher than when surveyed by the Ordnance Survey 

 (though the elevation is not given on the 6-inch maps), and the outline 

 of the loch, especially in the southern portion, was greatly altered in 

 consequence. 



A series of temperatures taken near the deepest part of the loch showed 

 a range of 4*6 Fahr., as shown in the following table : 



Surface... 59'6 Fahr. 



10 feet 58-9 



25 58-0 



50 56-8 



80 55-0 



Derclach Loch (see Plate XXXV.). A very small, narrow, and shallow 

 loch, lying close to the west of Loch Finlas. It is a little over half a mile 

 long, one-eighth of a mile broad, and 12 feet deep. The bottom at the 

 deeper part is flat, and 10 feet deep over a considerable area. The 

 maximum of 12 feet is close to the west end; the eastern part is very 

 narrow, irregular, and from 1 to 6 feet deep. The mean depth is 7J feet, 

 the area 38 acres, and the volume 12 millions of cubic feet. The area 

 drained is scarcely a square mile. No important stream enters, and the 

 burn flowing east to Loch Finlas is only about 100 yards long. The 

 shores are of peat and gravel, with rock exposed at several points. 

 The surface was 837'1 5 feet above sea-level on July 13, 1903. The 

 temperature was 58*4 Fahr. throughout. 



Loch Finla* (see Plate XXXV.). A small, narrow, dumb-bell-shaped 

 loch, with a straight axis running north-west to south-east, lying among 

 moorland, 1J miles to the west of Loch Boon. The hills on the north 

 rise to a little over 1000 feet (200 feet above the loch) ; on the south they 

 are higher, Craiglee attaining a height of 1716 feet. The loch is 1J miles 

 long and one-third of a mile broad in the north-western expansion. The 

 channel connecting the ends of the loch is three-quarters of a mile long, 

 for the most part less than 100 yards broad, and varies in depth from 

 6 to 18 feet in the centre. The north-western expansion is the deeper. 

 The bottom is irregular, with the maximum depth of 40 feet in the centre, 

 but other soundings up to 34 feet close inshore. The south-eastern ex- 

 pansion is much shallower, and nearly flat-bottomed, with a depth of about 

 10 feet, and a little depression of 26 feet at the end of the strait. The 

 mean depth is nearly 10 feet, the area about 138 acres, and the volume of 

 water 58 millions of cubic feet. The area drained is nearly 5 square miles. 

 The natural outflow is by the Garpel burn, issuing from the east end of 

 the loch ; but the water is now utilized as the water supply for the town 

 of Ayr. The surface was 829'65 feet above sea-level on July 13, 1903. 



