THE FRESH-WATER LOCHS OF SCOTLAND. 
17 
thus falls below sea-level, as indicated on Plate X. The cubic mass of 
water contained in the loch is estimated at 562,000,000 cubic feet, and 
the mean depth at 19| feet, or 26 per cent, of the maximum depth. 
The length of the loch is 110 times the maximum depth, and 427 times 
the mean depth. 
The bottom of the Lake of Menteith is apparently very irregular. 
The 10-feet line follows approximately the outline of the loch, except 
that it is considerably removed from the south and south-east shores, 
where the land is bordered by reeds; it also surrounds the islands of 
Inchmahome, on which the Priory is situated, and Inch Talla, on which 
the castle is situated, Dog Isle, and a submerged crannog covered by 
FIG. 11 . LAKE OE MENTEITH. 
( Photograj^h by G. W. Wilson.) 
four feet of water in the north-eastern angle of the loch at Port of 
Menteith. The area of the bottom covered by more than 25 feet of water 
is cut up into three portions. The eastmost of these 2 5 -feet depressions 
has a maximum depth of 48 feet ; the central 25-feet depression is almost 
triangular in outline, with a maximum depth of 49 feet. The westmost 
2 5 -feet depression is the largest and the deepest : it is almost divided 
into two halves by a narrow constriction between Inch Talla and Stable 
Point, the deepest water observed in the southern half being 49 feet, 
while the northern half contains the deepest water found in the loch. 
Here the bottom falls below the depth of 50 feet over an area of nearly 
32 acres, the 50-feet depression being about a third of a mile in length 
and over a sixth of a mile in maximum width. It encloses a small patch 
