274 BATHYMETEICAL SURVEY OF 



map is 1001 [feet above the" sea, though the date is not mentioned. The 

 temperature of the surface water was 49- 5 Fahr. 



Loch DocJiard (see Plate OXXVII.) lies about 3 miles to the west of Loch 

 Tulla, into which it drains. There are some huge boulders on the shore, 

 and the river both on entering and leaving the loch has considerable 

 volume, silting up having taken place at the inflow, while at the outflow 

 rock is exposed on both sides. The loch is somewhat irregular in^ outline, 

 trending east and west, and is about two-thirds of a mile in length. The 

 superficial area is about 86 acres, and the drainage area nearly 8 square 

 miles. The maximum depth of 42 feet was recorded near the centre of the 

 wide part of the loch. The volume of water is estimated at 44 million 

 cubic feet, and the mean depth at 1 2 feet. The loch was surveyed on May 

 18, 1903, but the level could not be ascertained, though it was estimated 

 from spot-levels to be about 735 feet above the sea. The loch is fairly 

 simple in conformation, the deep water occupying a central position, but a 

 sounding in 15 feet was taken towards the northern shore, surrounded 

 by depths exceeding 25 feet. A spit of sand and boulders projects into the 

 loch from the southern shore, and from its extremity a shoal or causeway, 

 covered by 2 or 3 feet of water, extends to the western shore ; in close 

 proximity to this shoal soundings in 17 and 18 feet were recorded. 



The surface temperature over the deep part of the loch was 48'0 Fahr., 

 whereas in the shallow bay at the east end the temperature of the surface 

 water was no less than higher, viz. o4 0< 0. 



LocJi Tulla (see Plate CXXVIII.) lies about 8 miles north-west of Tyii- 

 druni, and only 2 miles to the south of Lochan na h-Achlaise, in the Tay 

 basin. It trends in a north-east and south-west direction, and is 2^ miles 

 in length, and nearly a mile in maximum breadth, the mean breadth being 

 nearly half a mile. The superficial area is about 703 acres, or over a 

 square mile, and the drainage area about 57 square miles, including Loch 

 Dochard. The maximum depth of 84 feet was recorded in two places near 

 the centre of the loch, about a quarter of a mile to the north-east of the 

 central island. The volume of water is estimated at 1167 millions of. cubic 

 feet, and the mean depth at 38 feet. The loch was surveyed on April 16, 

 1903, the elevation above the sea being determined by levelling from bench- 

 mark as 542'3 feet. According to the hotel-keeper, the water was low at 

 the time, the range in level being about 6 feet. 



The loch is complex in conformation, due largely to the presence of a 

 small island (Eilean an Stalcair) near the middle of the loch, opposite the 

 exit of the river Orchy, in the vicinity of which the bottom is irregular, 

 and the contour-lines sinuous in character. The main body of water lies 

 to the north-east of the island, where there is a 50 -feet basin nearly 1J 

 miles in length, enclosing a 75-feet basin over three-quarters of a mile in 

 length. To the south-west of the island there is a small subsidiary 50 -feet 



