290 
BATHYMETRICAL SURVEY OF 
the latter locality formed the original rocky barrier of the lake, the 
depth of water below this level in Loch Garve is still 84 feet. 
Loch Achilty. — Though this lake is small, its extreme depth (119 
feet) is remarkable. There is no proof that it occupies a rock basin, but 
it is not improbable that such may partly be the case. Towards the 
east it has been filled in by the delta gravels of the Blackwater, and 
on the other side by those of the Conon at the time of the formation 
of the 100-feet beach. 
Loch Ussie is a shallow basin, 35 feet in depth, resting in drift; and 
Loch Ki^iellan appears to be banked by superficial deposits at the west 
end, while at its eastern margin the bituminous shales of the Old Red 
Sandstone are exposed. Its greatest depth is only 16 feet. 
Loch Morie is obliquely traversed by a line of fault, with a down- 
throw towards the south-west, that branches westwards in the upper 
part of the basin. Each branch shifts the outcrop of the zone of 
altered strata in contact with the mass of foliated granite already 
referred to. The stream issuing from the lake flows over a rocky barrier, 
but it is possible that there may have been a former outlet now concealed 
by drift. 
Loch Glass. — ^Round the north-east margin there are traces of 
terraces between Culzie Lodge and the foot of the lake. No rocky 
barrier appears till the Falls of Eillenach are reached, where the stream 
flows over a mass of conglomerate of Old Red Sandstone age at an 
elevation of about 680 feet. As the surface of the loch is 713 feet above 
Ordnance datum line, and the deepest sounding is 365 feet, it follows 
that the depth of water in Loch Glass below the level of the barrier at 
the Falls of Eillenach is 332 feet. 
Loch Eye lies on the stratified deposits of the 100-feet beach. 
Notes on the Biology of the Lochs in the Conon Basin. 
By James Murray. 
The lochs of the Conon basin, with the exception of Loch Eye, which 
will be separately noticed, have the plankton of a very uniform 
character. The fauna includes only those species which are common 
to the whole country, and calls for little detailed notice. The most 
important feature in it is the total absence of all those species of 
Eiaptomus (D. Wierzejskii, D. laticeps, D. laciniatus) which are 
common in the districts to the north and south of the Conon valley. 
This valley, extending nearly across Scotland, forms a line of inter- 
ruption in the distribution of those species, a line completed towards 
the west by Lochs Maree, Dhugaill, and Sgamhain, all of similar 
