244 
BATHYMETRICAL SURVEY OF 
same gillie stated that a shoal hank extended from Kuadh Bac na Moine 
in an approximately south-west direction towards the opposite shore ; 
this was confirmed by fishermen, and is probably indicated by the 
outward bend of the 50-feet contour-line at that place. 
The 100-feet contour-line is less sinuous in character than the 50-feet 
contour, the main basin being about 12 miles in length, extending 
from near the head of the loch to the narrows at Eilean Fhianain, 
with two small subsidiary basins — one off Budha Leathan, about 3^ 
miles from the foot of the loch, based on a sounding of 112 feet; 
the other between the promontory on the south-eastern shore called 
Rudha Torr a’ Chonnaidh and the outlying islands, about 7 miles from 
the head of the loch, based on a sounding of 148 feet. A remarkable 
rise in the bottom was observed within the main 100-feet basin, about 
a mile above the entrance of the river Polloch, where soundings of 
84 and 43 feet were taken, surrounded on all sides by about 150 feet 
of water. The contour of the lake-floor along this line of soundings is 
shown in cross-section C-I) on the map (Plate LII.). 
The main 200-feet basin is nearly 8 miles in length, approaching 
to within half a mile from the head of the loch, and extending as far 
down as Eileanan Comhlach. There are two small subsidiary basins, 
separated from the main basin by an interval of over half a mile, 
between the entrance of the Allt na Claise on the south-eastern shore 
and the entrance of the An Garbh-allt on the north-western shore. 
This line of soundings shows a curious configuration of the bottom, 
which rises in the central part of the loch and sinks again on both sides 
nearer the shore : thus, on proceeding from south-east to north-west the 
water deepens to 201 feet, then shoals to 122 feet, then deepens again to 
172, 209, and 224 feet, shoaling again towards the north-western shore. 
It is interesting to note the close proximity of these two small deep 
basins to the rise covered by 43 feet of water already mentioned. The 
200-feet contour shows a peculiar loop off the north-western shore, 
about 4 miles from the head of the loch, where the water shoals from 
199 to 163 feet. 
The principal 300-feet basin is distant about a mile from the head 
of the loch, and extends down the loch for over 4 miles, enclosing the 
deepest parts of the loch. Separated from this basin by an interval 
of a quarter of a mile (in which the greatest depth is 282 feet) is a 
second small basin based upon a sounding of 307 feet, and after a 
similar interval (in which the greatest depth is 284 feet) there is 
a third 300-feet basin 2 miles in length, having a maximum depth of 
385 feet. Within this third basin there is a slight rise of the bottom 
covered by 288 feet of water; the line of soundings on which this 
rise is situated is shown in cross-section E-F on map (Plate LIII.). 
There are two small basins with depths exceeding 400 feet, the 
smaller about 3 miles from the head of the loch, based on soundings 
