242 BATHYMETRICAL SURVEY OF 



mile ; there are no feeders of any importance, and the Twatt burn conveys 

 the overflow into Bixter Voe. 



On July 17, 1903, the surface was 77'9 feet above sea-level; on 

 October 24, 1877, the Ordnance Survey officers found it to be 78'7 feet. 

 The surface temperature was 54*8 Fahr. 



Loch of Collaster (see Plate C.) is a very small triangular loch, lying 

 1 mile north-west of Aithsting church. It measures fully one-third of a 

 mile from north to south, by one-fifth of a mile broad at the north end. 

 It is very shallow, the maximum depth of 10 feet being near the north end. 

 It receives on the west the Burn of Shunalittle from Loch Shunalittle. 

 The Twatt burn carries the overflow to Kirkhouse Water (not surveyed), 

 whence the Burn of Quinigill issues, and, joining the Twatt burn from 

 the Loch of North-house, enters Bixter Voe. The superficial area is 

 about 25 acres, the mean depth nearly 6 feet, and the volume of water 

 7 millions of cubic feet; three soundings in the maximum depth of 

 10 feet were taken near the northern end. It drains an area of less 

 than half a square mile. The height of the loch above sea-level could 

 not be ascertained. 



On July 14, 1903, the surface temperatures was 53'0 Fahr. 



Loch of Strom (see Plate OIL) lies 5 miles due north of Scalloway, and 

 is one of the longest lochs in Shetland, but is very narrow. It is a tidal 

 loch. Its axis runs nearly due north and south. The valley in which 

 it lies is here very narrow, and the hills which bound it slope steeply 

 into the loch. On the east the hills are higher and covered with 

 heather, and rock shows at many points on. the lake-shore; on the 

 west the lower hills are rugged and covered with grass ; rock shows 

 at the promontory called Quoy ness, on the west shore, and at the 

 extreme south end. South of the Strom bridge the west shore is a terrace 

 of gravel with boulders. There is rock at the north end of Strom 

 bridge, and at the sea end of the Strom on the south side. The tide 

 appears to have little effect on the level of the loch, which was 

 0'5 foot above sea-level on the date of the survey (August 1, 1903), but it 

 must renew the water with sufficient frequency to permit of the growth of 

 fucoids and other marine organisms over the whole of the bottom, even to 

 the extreme north. The northern part of the loch, rather more than half 

 the length, is very narrow; south of Quoy ness is a broader portion. 

 The length is a little over 2J miles, which slightly exceeds that of the 

 Loch of Cliff, unless the narrow eastern arm is included in the length of 

 that loch. The greatest breadth, one-third of a mile, is just south of 

 Quoy ness. 



The Loch of Strom is very shallow. East of Quoy ness, on each side 

 of the narrow island, the depth is only 6 feet, and there is deeper water 

 both to the north and south. In the northern basin, the central part of 



