228 
BATHYMETRICAL SURVEY OF 
somewhat more than half a mile, westward, and enters the sea at the 
village of Birsay. On August 30, 1906, the surface was 50*85 feet above 
the sea. The temperature was 57°*3 Fahr. throughout. 
Loch of Hundland (see Plate XCIII.) is a triangular loch of moderate 
size, lying between the larger Lochs Swannay and Boardhouse. The land 
is higher on the east, where Hundland hill rises to 150 feet above the 
surface. The west side is low moor. The shores are stony, and there 
are many stony islands and shoals. The bottom, paved with flat stones, 
is visible at depths of 4 to 5 feet. In the deepest part of the loch are 
large beds of Fotamogeton^ reaching the surface from a depth of 7 feet. 
The length from north to south is Ij miles, and the greatest breadth 
slightly exceeds half a mile. The bottom is flat, and in the great central 
portion varies between 5 and 7 feet in depth. The maximum of 7 feet 
occurs in a narrow strip near the eastern shore, in the widest part of the 
loch. The mean depth is about 4 feet, the superficial area nearly half 
a square mile, and the volume 51 millions of cubic feet. The drainage 
area is large, including the Durka dale, a glen about 5 miles long, and 
measures 9^ square miles. The Kirbuster burn flows from the south-east 
corner to the Loch of Boardhouse through a grassy flat. Rock is seen 
in the bed of the stream at the bridge carrying the public road. On 
September 1, 1906, the surface was 89*7 feet above sea-level. The 
temperature was 62°*0 Fahr. throughout. 
Loch of Skaill (see Plate XCIY.) is a small loch on the west coast of 
Pomona, half a mile south-east of the Bay of Skaill. It is of triangular 
form, and broadest at the west end. It lies amid stony fields, and a boggy 
flat intervenes between the loch and the Bay of Skaill. Through this the 
outflow goes by a small burn, utilized as a mill stream. Some rock is seen 
on the northern shore and close to the outflow. The island in the centre 
is artificial, formed of flat stones, and measures about 20 yards across. 
The length is nearly one mile, and the maximum breadth half a mile. 
The bottom is flat and covered by a yellowish mud. The western bay is 
filled with reeds. The maximum depth is 4 feet, the mean depth 2 feet, 
the area a quarter of a square mile, and the volume 14 millions of cubic 
feet. The loch drains an area of one square mile. 
On August 29, 1906, the surface was 26*9 feet above sea-level, and the 
temperature was 58°*6 Fahr. 
Muchle Water (see Plate XCI.) is a narrow straight loch, lying at 
a considerable elevation (322 feet) among the hills, in the island of 
Rousay. The shores are rocky on the western side of the loch. The 
south shore in the eastern half is a high bank of peat. There is a broad 
stony beach. The length is 1| miles, and the breadth nearly a quarter of 
a mile. It is a simple basin, gradually deepening from ^the west end 
