208 
BATHYMETRICAL SURVEY OF 
a straight line from north to south, is miles, and the greatest breadth 
scarcely half a mile. The loch is shallow throughout, slightly deeper 
near the two expanded ends, in the southern of which is a depth of 20 feet, 
and in the northern the maximum of 25 feet. The mean depth is nearly 
9 feet, the area about 131 acres, and the volume 49 millions of cubic feet. 
The drainage area is nearly 4 square miles in extent. Several large burns 
come down from the ridge to the west. The discharge is by the Amhuinn 
Mhor, a mile long, eastward into the head of Loch Erisort. On the date 
of the survey (August 5, 1903) the surface was 47 ’9 feet above sea-level. 
The temperature varied 2° from surface to bottom ; surface, 68°*0 Fahr. ; 
15 feet, 56°-4 ; and 23 feet, 56°‘0. 
Loch Valtos (see Plate LXXX.) is a small loch to the west of Laxey, 
on the north side of Loch Erisort. The surrounding land is low. In form 
it is narrow, with the axis curved and running south-west to north-east, 
while a narrow arm runs south-east from the middle of the loch. The 
length is two-thirds of a mile, and the greatest breadth, measured into the 
south-eastern branch, over a quarter of a mile. There is a constriction 
one-fifth of a mile from the west end of the loch, in which is the maximum 
depth, 27 feet. East of the constriction it is shallow, the greatest depth 
being 13 feet — the little round western basin is slightly deeper, 21 feet close 
to the north shore. The mean depth is over 7 feet, the area about 51 acres, 
and the volume 16 millions of cubic feet. The drainage area, which 
is that of fhe whole Laxey basin, is 22 square miles. The river Laxey 
just touches the northern extremity of the loch, and there are no other 
feeders of any size. On the date of the survey (August 15, 1903) the 
surface was 24*05 feet above sea-level. 
The temperature at the surface was 59°*2 Fahr., at 15 feet 58°*0, and 
at 27 feet 57°*6. 
Loch nam Faoileag (see Plate LXXX.) is a small but relatively broad 
loch immediately to the east of Loch Trealaval. It lies amid low moor- 
land, at the same level as Loch Trealaval, and is commonly regarded as a 
portion of that loch. In form it is oblong, with very undulating shores, 
and measures two4hirds of a mile from east to west by one-third of a mile 
broad. The loch is shallow, in the central part almost flat and about 
10 feet deep, the two small depressions of greater depth, 21 and 22 feet 
respectively, being close to the shore and at opposite ends of the loch. 
The mean depth is about 9 feet, the area about 100 acres, and the volume 
38 millions of cubic feet. The drainage area of 17 square miles includes 
Loch Trealaval, Loch Fadagoa, and numerous smaller lochs. There is 
scarcely any inflow except through Loch Trealaval. The large river 
Laxey flows out from the north-east corner. 
Loch Trealaval (see Plate LXXX.) is a large loch of very irregular 
form, lying about 2 miles north of Balallan on Loch Erisorti The sur- 
