264 



BATHYMETRICAL SURVEY OF 



feet. The loch was surveyed on July 30 to August 1, 1902, and the 

 elevation of the lake-surface, on commencing the survey, was found, by 

 levelling from bench-mark, to be 508*4 feet above the level of the sea ; 

 when levelled by the Ordnance Survey officers on July 3, 1868, the 

 elevation was 507'9 feet above sea-level. 



Loch a' Chroisg forms a simple basin with no pronounced irregu- 

 larities of the lake-floor, as is well shown by the longitudinal and 

 cross sections on the map; the contour-lines enclose continuous areas 

 following approximately the outline of the loch. The 100-feet basin 



FIG. 45. LOCH A' CHROISG, LOOKING WEST. 



(Photograph by Mr. T. N. Johnston, M.B., C.M., F.R.X.K.) 



exceeds 2 miles, and the 50-feet basin is nearly 2| miles, in length, 

 approaching in each case rather nearer to the east than to the west end 

 of the loch, while the small 1 50-feet basin lies nearer to the west than 

 to the east end. The approximate areas between the consecutive 

 contour-lines drawn in at equal intervals, and the percentages to the 

 total area of the loch, are as follows : 



Oto 50 feet 

 50,, 100 

 100,, 150 

 Over 150 , 



241 acres 

 186 

 195 



640 , 



37 '7 per cent. 

 29-0 

 30-5 

 2-8 



100-0 



The slightly larger area between 100 and 150 feet than between 50 

 and 100 feet indicates the flat-bottomed character of the deeper part 



