THE FRESH-WATER LOCHS OF SCOTLAND. 
351 
where a sounding in 48 feet was taken about 50 feet from shore. The 
area of the lake-floor covered by less than 50 feet of water is about 
80 acres, or 51 per cent, of the total area. 
Temperature Observations . — The following series of temperatures, 
taken in the deepest part of the loch, show that the whole body of 
water was practically uniform in temperature ; — 
Surface 
25 feet 
50 
>> 
75 
90 
110 
48° -2 Fahr. 
48° -2 „ 
48° -0 „ 
48° -0 ,, 
48° -0 „ 
47° -9 „ 
The particulars regarding the lochs in the Beauly basin are collected 
together in the table on p. 350 for convenience of reference and com- 
parison. From this table it will be seen that in the thirteen lochs 
under consideration, which cover an area of 5| square miles, about 850 
soundings were taken, or an average of 146 soundings per square 
mile of surface. The aggregate volume of water contained in the lochs 
is estimated at 11,230 millions of cubic feet, and the area draining into 
them is over 215 square miles, or 37 times the area of the lochs. 
Geological Notes on the Lochs within the Basin of the Farrar. 
By B. N. Peach, ll.d., f.r.s., and J. Horne, ll.d., f.r.s. 
The mapping of the western part of the Beauly basin by the 
Geological Survey has only been carried southwards to the watershed 
between Glen Strath Farrar and Glen Cannich, and hence the following 
notes are confined to the lakes lying within the basin of the Farrar. 
This area is entirely occupied by the metamorphic rocks of the High- 
lands, which have been arranged in two divisions — (1) an older series, 
which has been correlated with the Lewisian or Archaean gneiss of the 
West Highlands; and (2) a group of crystalline schists, termed the 
Moine series by the Geological Survey, which are regarded as altered 
sediments, and are supposed to rest unconformably on the older 
Lewisian gneiss. 
The members of the older series comprise hornblendic and biotite 
gneisses and ultrabasic masses, together with crystalline limestone, 
graphite schists and eclogites, which resemble the rocks of Lewisian age 
in the neighbourhood of Glenelg. The Moine series includes two 
prominent subdivisions — (1) flaggy and massive quartz-biotite 
granulites ; and (2) muscovite-biotite schists, the latter probably 
representing an argillaceous phase of sedimentation. In the basin of 
