198 THE ERESH-WATER LOCHS OF SCOTJ.AND 
sheltered bays or creeks, no phanerogams can exist at the bottom 
within 4 or 5 feet of the surface, on account of the erosive action 
of the waves ; so that there remains a very narrow zone available for 
such plants, and as a rule none occur. This is a common feature not 
only of Loch Ness, but of all the large lochs that I have examined. 
The sudden rise and fall of the water of Loch Ness, due to its 
being fed by eight good-sized rivers as well as by about forty burns, 
yet having but one effluent, must be mentioned as being a further 
factor antagonistic to the well-being of plants. The records kept by 
the Canal authorities at Fort Augustus give the maximum rise of 
7 feet 4 inches from the lowest in dry periods to the highest in wet 
weather. A rise of 2 feet within a few hours is quite a usual 
occurrence. This becomes more comprehensible when it is remembered 
that a rainfall of 2J inches means the addition of 100 millions of tons 
of water to the drainage area, most of which speedily finds its way 
into the loch. At Loch Mhor there is a rise and fall of 22 feet, 
caused by artificial agency ; the effect of this upon vegetation is there 
very evident. 
At the south-west end of the loch, from Borlum to the em- 
bouchure of the river Tarff, the shore consists of gravel and sand, 
and forms a large high beach. On the crest and rear of this beach 
there is a considerable flora, ranging, in accordance with the oeco- 
logical conditions, from xerophilous plants in the more elevated parts 
to hygrophilous vegetation at a lower level. Behind the beach there 
is an extensive marsh containing the plants usual to such an environ- 
ment that are common to the district. Along this beach no semi- 
aquatic plants occur in the loch, on account of the waves. From the 
beach the aquatic flora extends over the bottom from about 5 feet 
to ^0 feet deep, the chief plants being Littorella lacustris, Isoetes 
lacustris, Myriophyllum alterniflorum, Nitella opaca, and Fontinalis 
antipyretica ; an occasional plant of the two last-mentioned may be 
found even to a depth of 40 feet. The bottom here is mostly of 
gravel down to 30 or 40 feet ; in deeper w^ater mud obtains. 
The Caledonian Canal entrance into Loch Ness has a luxuriant 
aquatic flora upon its embankments, but this is almost limited to 
Lobelia Dortmanna, Juncus fluitans, Callitriche hamulata, and Myrio- 
phyllum alterniflorum. From here, past the embouchure of the 
river Oich to the point beyond the railway pier, the flora is ex- 
tremely scanty. There is practically no shore ; the rocks have 
occasional patches of Nardia emarginata or Scapania undulata, and 
are sometimes green with Zygnema. Rounding the point, we enter 
Inchnacardoch Bay. The water over a considerable area of this bay 
is less than 20 feet deep, with a sandy or muddy bottom which bears 
a luxuriant vegetation. The only island of Loch Ness — Cherry 
