30 BATHYMETRIOAL SUEVEY OF 



LOCHS OF THE SCOUKIE BASIN. 



THE two principal lochs within this basin (Lochs an Laig Aird and 

 a' Bhaid Daraich) were sounded by the Lake Survey, and were found 

 to form a complete contrast both in outline and conformation. Loch 

 an Laig Aird is most irregular in these respects, while. Loch a' Bhaid 

 Daraich is quite simple. The overflow from Loch an Laig Aird is carried 

 by the Allt Loch an Laig Aird into Loch a' Bhaid Daraich, which flows by 

 the short stream Allt a' Mhuilinn into Scourie bay on the west coast 

 of Sutherland. 



Loch an Laig Aird (see Plate XL). Loch an Laig Aird is situated 

 about a mile to the north-east of Scourie, and half a mile to the south* 

 of Loch nam Breac. The waters of the loch almost entirely encircle 

 a large promontory of land, the connecting isthmus being only about 

 100 feet across, and cover an area of about 67 acres. The loch is on 

 the whole shallow, the area of the bottom covered by less than 20 feet 

 of water being about 51 acres, or 76 per cent, of the total area. The 

 deepest part of the loch is in the arm stretching south : westwards from the 

 large promontory, where there is a long narrow basin exceeding 40 feet in 

 depth, the deepest sounding in 42 feet having been taken close to the 

 southern shore, about a quarter of a mile from the south-western extremity 

 of the loch, and only about 40 feet from shore, so that the slope of the 

 bottom at this place is very steep. A steep slope also occurs near the 

 south-western extremity of the loch, where soundings in 13 and 14 feet 

 were taken about 10 feet from shore. In the broad arm to the east of the 

 large promontory the maximum depth observed was 31 feet, and a similar 

 depth was found to the north-west of the large promontory. The loch 

 was surveyed on September 9, 1902, but the elevation of the lake-surface 

 above the sea could not be determined. 



Temperature Observations. A series of temperatures taken at 5 p.m. on 

 the date of the survey, in the deepest part of the loch, gave the following 

 results : 



Surface 57 0< 2 Fahr. 



20 feet 56-2 



35 56-l 



Loch a' Bhaid Daraich (see Plate XL). Loch a' Bhaid Daraich is 

 situated near the village of Scourie, and little more than a quarter of a 



