146 
Proceedings of the Royal Society of Edinburgh. [Sess. 
but is not visibly connected with it. It is 39 feet above sea level, is 
about J mile long and J mile broad, wdth a maximum depth of 42 
feet. The surrounding features are similar to those of Loch Magillie, 
as also is the margin. The west shore has a zone of Heleocharis palustris, 
as at White Loch, behind which, in some places, there is a narrow strip of 
marsh with the usual variety of plants. At other parts a narrow border 
of stones intervenes between the water and the meadow, this shore, as at 
Loch Magillie, being occupied by Juncus effusus. Nowhere is there any 
broad zone of marsh. The stones from the margin to a depth of from 2 
to 3 feet are often thickly overgrown with Cladophora canaliculata, etc. 
A marked feature of this loch is the vast quantity of plankton organisms, 
which render the water quite turbid ; in addition to which, there are such 
enormous numbers of Gloeotrichia Pisum that in some parts the water 
resembles pale green paint. No doubt the turbidity of the water of this 
loch accounts in some measure for the poor bottom flora. The Rev. Mr 
Paton, whose manse is pleasantly situated on a peninsula jutting into the 
loch, informed me that in the winter the turbidity disappears, and then it 
is possible to see the bottom to a depth of 6 feet. Obviously the clearness 
of the water in winter has no effect upon the extension of a bottom flora 
of Phanerogams. No plants occur at a greater depth than about 6 feet, 
because in deeper water there is a deposit of vegetable detritus lying upon 
mud. Ranunculus circinatus and Callitriche autumnalis are the only 
dominant submerged Phanerogams, and both are extremely abundant. 
Potamogeton perfoliatus abounds in a few spots ; Littorella lacustris and 
Nitella opaca occur, but not plentifully. These few species were the only 
submerged plants I could find. The marginal flora beyond what has been 
mentioned is of little interest. 
There are three small lochs lying close to the railway, about a mile 
west of Castle-Kennedy station. The easternmost one was dry at the time 
of my visit, the site being covered with Juncus effusus and other marsh 
plants. The others are entirely overgrown with aquatic vegetation, and 
are so surrounded with extensive marsh that the water cannot be 
approached. No boat being available, I am unable to give a proper 
account of their floras, but some of the features are illustrated in figs. 7 6 
to 78. 
The plants observed at the lochs described after Black Loch, but not 
hitherto mentioned, as they form no prominent features at these lochs, are 
as follows : — Iris Pseud-acorus, Carex rostrata, Glyceria fluitans, Sparganium 
ramosum, Phalaris arundinacea, Comarum palustre, Juncus effusus, Mentha 
sativa, CEnanthe crocata, Ranunculus Flammula, Polygonum amphibium, 
