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 Kinellan 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 MUREAY. 



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 

 Diaptomus (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 



