192 BATHYMETRICAL SURVEY OF 



Loch nan Geireann (see Plate LXXIV.). As there are two lochs of 

 the same name, this, the larger one, is locally distinguished as Geireann 

 Mill. The stream from the loch formerly supplied a mill, now in ruins. 

 Though one of the largest lochs on the island (it comes fourth ia point 

 of length), Loch nan Geireann is so generally similar to Loch Scadavay 

 that a very short description will suffice. It is 2 miles in length and 

 three-quarters of a mile in greatest breadth. Unlike Lochs Scadavay and 

 nan Eun, the bottom is even, and there are no deep holes, though many 

 small islands and numbers of large stones project above the surface. The 

 area is two-thirds of a square mile, and the volume 121 millions of cubic 

 feet. The maximum depth is 18 feet, and the mean depth 6 feet. The 

 shores are almost everywhere of rock, though there are some stony stretches. 

 The rock is in places covered with deep peat and heather ; there are many 

 boulders scattered around, and some perched blocks. There are many 

 bays with white sand, and a great part of the bottom is sandy. The 

 distribution of the sand under the influence of wind probably accounts 

 for the filling up of holes and the general uniformity of the bottom. The 

 short stream conveying the overflow to the sea has a rocky channel. The 

 drainage area extends to 6J square miles, and includes some small lochs 

 which were not surveyed. The principal streams enter on the west. 

 The loch was surveyed on May 16 to 19, 1904, when the level was found 

 to be 16-4 feet above the sea; on September 23, 1875, the Ordnance 

 Survey found it to be 17 '3 feet. The temperature on May 19 was 52'0 Fahr. 

 at the surface, and 51-5 at 10 feet. 



Loch Hosta (see Plate LXXIIL). A small loch in the extreme west 

 of the island. It is of oblong form, half a mile in length by fully a 

 quarter of a mile in greatest breadth. It differs from most of the other 

 lochs in having a simple little-indented outline. The basin is simple, 

 the sides sloping gently all round, but a little more steeply on the north- 

 east side, to the maximum of 31 feet nearly in the centre. On June 18, 

 1904, the surface was 23'5 feet aboye sea-level; on September 11, 1875, 

 the Ordnance Survey found the level to be 23'0 feet. A small burn, half 

 a mile long, runs west to the sea at Raikinish. 



LocJi Oban a j Chlachain (see Plate LXXV.). A small tidal loch, 

 nearly a mile long by a quarter of a mile broad, draining into the Sound 

 of Monach, opposite the island of Baleshare. It runs from west to east 

 towards the head of Loch Eport, which it so nearly approaches that the 

 island is almost cut across, the isthmus being less than a quarter of a mile 

 across. The loch consists of a narrow western part, filled with seaweeds, 

 and a triangular eastern part, with an almost level bottom about 14 feet 

 deep, the maximum of 19 feet being recorded close to the south shore. 

 The tides affect the level more than in the other tidal lochs sounded. 

 On June 1, 1904, the level of the surface was 3' 75 feet above the sea, and 



