208 BATHYMETRICAL SURVEY OP 



a straight line from north to south, is lj 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, 58 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 the 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. 



LocJi 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 two-thirds 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 corned. 



Loch Trealaval (see Plate LXXX.) is a large loch of very irregular 

 form, lying about 2 miles north of Balallan on Loch Erisort, The sui> 



