118 
BATHYMETRICAL SURVEY OF 
were recorded, surrounded in each case by deeper water. These shallow 
soundings mark the position of a rocky ridge, said to cross the loch, and 
to be a continuation of the rocky ridge on the east shore, now used as a 
quarry. About midway along the eastern shore there is a slight con- 
striction in the outline of the loch at the entrance of the Allt Bhaltair, 
apparently due to the material brought down by that stream, and in 
this position a slight shoaling of the bottom in the centre of the loch is 
observable, the depth being 73 feet, with two soundings of 77 feet to the 
north, and soundings of 77 and 79 feet to the south. The 2 5 -feet basin 
is about three-quarters of a mile in length, approaching to within 100 
feet from the northern end, and a quarter of a mile from the southern 
end. The slope of the bottom is steeper off the western than off the 
eastern shore; near the middle of the western shore a sounding of 40 
feet was taken about 50 feet offshore, giving a gradient of 1 in U25. 
The area of the lake-floor covered by less than 25 feet of water is about 
85 acres, or 52 per cent, of the total area of the loch ; that covered by 
water between 25 and 50 feet in depth is about 36 acres, or 22 per 
cent. ; that covered by water between 50 and 75 feet in depth is about 
36 acres, or 22 per cent. ; and that covered by more than 75 feet of 
water is about 7 acres, or 4 per cent, of the entire area of the loch. 
The flat-bottomed character of the deep basin is well brought out by the 
fact that the area between the 25- and 50 -feet contour-lines is almost 
identical with the area between the 50- and 75 -feet contours. Loch 
Turret was surveyed on June 9, 1903, and the elevation of the lake 
surface above the sea, measured from the spot-level 1145 on the east 
shore, was determined as being 1132 feet. The water in the loch was 
high on the date of the survey. 
T emxjerature Ohser vat i oils . — The temperature of the surface water 
on commencing the survey at 9 a.m. was 60°*0, and a series of tem- 
peratures taken later in the deepest part of the loch gave the following 
results : — 
Surface 
10 feet 
15 „ 
25 „ 
50 „ 
/5 ,, 
(j0° 8 Fahr 
59° -0 ,, 
54° -0 ,, 
47° -7 ,, 
44° -8 „ 
44°-4 „ 
This series shows a range of temperature from surface to bottom 
amounting to 16°-4, there being a fall of 5°*0 between 10 and 15 feet, 
one of 6°*3 between 15 and 25 feet, and one of 3° between 25 and 50 
feet; the decrease of temperature between 10 and 15 feet was thus 
equal to 1° per foot of depth. 
Loclian U aine (see Plate XXXII.). — Lochan Uaine, at the head of 
Glen Turret, lies in a corrie; its shores are peat, and the bottom weedy. 
