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 in 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 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 LXXIII.). — 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 above 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. 
Loch Ohan a’ Ghlachain (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 
