THE FRESH-WATER LOCHS OF SCOTLAND. 19 



LOCHS OF THE THUKSO BASIN. 



TOWARDS the headwaters of the river Thurso there are several small 

 lochs, the most important being Loch More, which was the only one 

 sounded by the Lake Survey. This loch, which must not be confounded 

 with the larger Loch More in Sutherlandshire, is famous for its salmon 

 and trout fishing ; the large area of country draining into it is a striking 

 characteristic. 



Loch More (see Plate VI. j. Loch More lies about 13 miles to the 

 south of Thurso, the overflow from the loch being carried by the river 

 Thurso, after a long and devious course, into Thurso bay. The loch is 

 irregularly subcircular in outline, with a maximum diameter in a north 

 and south direction of less than a mile, the mean breadth being one-third 

 of a mile. The superficial area is about 177 acres, or a quarter of a square 

 mile, and the area draining into it is about 67^ square miles an area 

 24< > times greater than that of the loch. The maximum depth of 7 feet 

 was observed near the eastern shore, off the mouth of the outflowing river. 

 The volume of water is estimated at 32 million cubic feet, and the mean 

 depth at 4 feet. The loch was surveyed on October 9, 1902, when the 

 elevation of the lake-surface above the sea was found by levelling from 

 bench-mark to be 381 '4 feet ; when levelled by the officers of the Ordnance 

 Survey in July, 1870, the elevation was 381*0 feet above sea-level. 



Like most of the Caithness lochs, Loch More is a shallow, flat-bottomed 

 basin. Most of the soundings were taken in depths of 5 and 6 feet ; the 

 deepest cast in 7 feet was taken about 100 yards from the eastern shore 

 where the river Thurso flows out, while along the southern and northern 

 shores the bottom is being silted up by the deposition of material laid 

 down by the Strathmore water and the Sleach water. The area of the 

 lake- floor covered by less than 5 feet of water is about 92 acres, or 52 

 per cent, of the total area of the loch. On the date of the survey, tem- 

 perature observations gave 46'0 Fahr. at the surface and at a depth of 

 3 feet, while a reading at 6 feet gave 45 : - 8. 



