226 
BATHYMETRICAL SURVEY OF 
Locli of Harray. It is surrounded by a boggy flat, except on the north, 
where the Hill of Greenay rises. Rock is seen at several points on the 
north-east shore. The length is fully half a mile, and the breadth fully 
a quarter of a mile. The bottom is flat, with a maximum depth of 3 feet, 
and a large area of this same depth. The north-west corner is filled with 
reeds. The mean depth is feet, the area about 77 acres, and the volume 
5 millions of cubic feet. The drainage area measures fully 3 square 
miles. The outflow is westward by a small stream, utilized as a mill 
stream, into the Burn of Warth. The surface was 51*7 feet above sea- 
level on September 6, 1906. 
Loch of Ishister (see Plate XCI.). — A small loch, square or somewhat 
cruciform in shape, near the Church of Twatt, and miles south of the 
Loch of Boardhouse. It is surrounded by extensive boggy flats, especially 
to the west, so that a rise of even a foot in level would greatly extend 
the area of the loch. It is extremely shallow, and much obstructed by 
stones. The length from north to south is nearly two-thirds of a mile ; 
the breadth from east to west is a little less. The greatest depth, 3 feet, 
is at the east end. The mean depth is IJ feet, the area about 80 acres, 
and the volume 5 millions of cubic feet. The drainage area is square 
miles. A drain with sluice leads to the Loch of Banks. The surface 
temperature was 64° 6 Fahr. on September 1, 1906, the highest observed 
in Orkney. The bottom is free from weeds, except in the southern corner, 
and covered with grey clayey mud. The level was estimated at about 
40 feet above sea-level. 
Loch of Kirhister (see Plate XCII.). — The Loch of Kirbister (or Loch 
of Orphir) is a loch of moderate size, and somewhat triangular shape, 
in the parish of Orphir, 5 miles south-west of Kirkwall. It lies amid 
cultivated land in a broad valley between hills of over 700 and 800 feet 
respectively. It is 1^ miles long, and fully half a mile broad. The 
bottom is almost perfectly flat, a great central area being uniformly 
5 feet deep. The maximum depth is 6 feet, and the mean depth 4 feet. 
The area of the surface is about 227 acres, and the volume of water 
41 millions of cubic feet. The drainage area measures 8 square miles. 
The largest burns are those entering at the two ends of the loch. The 
outflow is near the southern end, by a mill burn, about half a mile long, 
with a rocky channel, flowing into Waulkmill bay. The surface was 
52T feet above sea-level on August 14, 1903. The surface temperature 
was 57°'0 Fahr. 
Loch of Tankerness (see Plate XCII.) is a triangular loch of moderate 
size, near St. Andrew’s church, .4 miles east of Kirkwall, surrounded 
by pasture and wet meadows. It is nearly a mile long by half a mile 
broad. It is shallow and flat-bottomed, very gradually deepening from 
