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 
riG. 45. LOCH A- CHROISG, LOOKING WEST. 
(Photograph by Mr. T. N. Johmton, M.B., C.M., F.R.S.E.) 
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 150-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 : — 
0 to 
50 feet 
241 acres 
37*7 per cent. 
50 „ 
100 „ 
186 „ 
29*0 ,, 
100 „ 
150 „ 
195 „ 
30*5 
Over 
150 „ 
18 „ 
2*8 „ 
640 ,, 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 
