96 
BATHYMETRICAL SURVEY OF 
65 acres, or one-tenth of a square mile, and it drains an area of over 3J 
square miles — an area 37 times greater than the area of the loch. Over 
60 soundings were taken, the maximum depth observed being 9 feet. 
The volume of water contained in the loch is estimated at 9,818,000 
cubic feet, and the mean depth at 3^ feet, or 39 per cent, of the 
maximum depth. The length of the loch is 550 times the maximum 
depth and 1430 times the mean depth. Loch Con is very shallow, and 
the central constriction cuts it into two basins, the deepest water being 
found near the east end, where two soundings of 9 feet were taken, 
while a sounding of 8 feet was taken in the basin to the north-west of 
the constriction. The area of the lake-floor covered by less than 5 feet 
of water is about 51 acres, or 78 per cent, of the total area of the loch. 
Loch Con was surveyed on July 4, 1903, but the level above the sea 
could not be determined with certainty because of the disparity between 
the spot-levels around the loch. The loch was about its lowest on the 
date of the survey, and drift-marks were observed about 3 feet above the 
water. The temperature of the surface water on commencing the survey 
at 3 p.m. was 54°-3 Fahr., and at 5 p.m. readings at the surface and at 
a depth of 8 feet both gave 55°'0. 
Loch Tilt (see Plate XXVIII.). — Loch Tilt, at the head of the glen 
of that name, consists in reality of two lochs, a broad burn flowing 
from the larger (northern) loch to the smaller loch, which is about one 
foot lower and full of weeds. The larger loch is nearly half -filled with 
weeds (^Equisetum), and the bottom is stony where free from weeds. 
The shore is stony, and the loch is surrounded by an almost flat terrace 
of peat with stones, with high, rounded, heather-clad hills on the west 
side. Loch Tilt is over one-third of a mile in length, and one-fifth of a 
mile in maximum breadth, the mean breadth being about one-thirteenth 
of a mile, or 22 per cent, of the length. Its waters cover an area of 
about 17 acres, and it drains an area twenty-one times greater — an 
area of nearly two-thirds of a square mile. Over 20 soundings were 
taken, the maximum depth observed being 5 feet. The volume of water 
is estimated at 1,839,000 cubic feet, and the mean depth at 2J feet, or 
50 per cent, of the maximum depth. Loch Tilt is shallow, the great 
majority of the soundings giving depths of 3 and 4 feet, only two 
soundings of 2 feet and two soundings of 5 feet being recorded. The 
deeper water occurs off the eastern shore, one sounding of 5 feet having 
been taken about 60 feet from that shore, giving a gradient of 1 in 12. 
Weeds are abundant off the south-western shore, and in the northern 
angle of the loch, where there are many large stones in the water. 
Loch Tilt was surveyed on July 9, 1903, and the level of the surface 
was determined, by levelling from bench-mark, as being 1653*5 feet 
above the sea. The water in the loch was low, and drift-marks were 
