198 
BATHYMETRICAL SURVEY OF 
7*2 feet. If there be no error in this measurement the tide must some- 
times enter the loch, and the local gillies stated that this was so. Never- 
theless the water is fresh enough to be drunk, and maintains the usual 
fresh-water fauna. Through so many narrow and shallow channels it is 
probable that the tides can have little effect on the salinity of the more 
distant parts of the loch. 
On June 11, 1904, there was a difference of 7°-6 between the surface 
and the bottom temperatures. The great part of the difference, 4°'5, 
occurred between 35 and 40 feet, as shown in the following table : — 
Surface ... 
58°-8 Fahr. 
25 feet . . . 
57°'2 „ 
35 „ ... 
56°-8 „ 
40 „ ... 
52°-3 „ 
50 „ ... 
51°-2 „ 
72 „ ... 
5U-2 „ 
Loch an lasgaich (see Plate LXXV.). — A little loch lying west from 
Loch Caravat and draining into it. It is fully half a mile long, by a 
quarter of a mile in greatest breadth. It is of the usual irregular outline 
and uneven bottom, and is studded with small islands. A great part of it 
is less than 8 feet deep, and the maximum of 16 feet is quite close inshore 
towards the east end of the loch. The surface is 11 *2 feet above sea-level. 
Loch ’ic Colla (see Plate LXXV.). — An extremely irregular loch 
(locally called Loch McColl), consisting of several narrow arms almost cut 
off from one another. It is a mile long, by half a mile in greatest breadth. 
The south portion has an uneven bottom, the deepest sounding in the loch 
(34 feet) having been taken near the island towards the east end, and 
a depth of 26 feet occurs close to the east end. The north portion has 
a fairly deep basin at its west end, where the maximum depth is 33 feet. 
A lesser basin of 22 feet in depth lies to the east of this. Loch Tc Colla, 
on June 9, 1904, was 16T feet above sea-level. Rock is seen at intervals 
all round the shore, but the stream, about 75 yards long, flowing into Loch 
Caravat, has a stony channel. 
In the deep part the range of temperature from surface to bottom was 
nearly eight degrees, wdiich occurred between the depths of 25 and 33 feet, 
the readings at the surface and at 25 feet being identical — ■ 
Surface - 60'^’2 Fahr. 
25 feet 60°-2 „ 
33 „ 52°-3 „ 
Loch cm t-Seasgain (see Plate LXXV.). — An insignificant narrow strip 
of w^ater, partly choked with w^eeds, lying south from Loch Tc Colla. 
Though distinguished by a name of its own, it was at the same level as 
Loch ’ic Colla, and really forms part of it. The maximum of 18 feet is 
found in a little hole at the east end. 
