THE DEPOSITS OF THE SCOTTISH 
FRESH-WATER LOCHS 
By W. a. CASPARI, B.Sc, Ph.D., F.I.C. 
(Assistant to Sir John Murray, K.C.B. ) 
In the course of the survey of the fresh-water lochs of Scotland 
some seven hundred samples of bottom-deposits were brought up, 
and eventuallv sent to the Challenger Office at Edinburgh. No 
systematic plan was adopted in collecting the deposits, and therefore 
some lochs are represented by a large series of samples, others by 
only a few, and others again (small lochs and reservoirs) by none 
at all. To some extent this is due to the practical difficulties of 
sampling, in that the sounding-tube frequently came up empty, or 
the material slipped out before it could be secured. Nevertheless, 
the material at hand is both plentiful and interesting. It has now, 
therefore, at the suggestion of Sir John Murray, been submitted to 
laboratory examination. 
With a few exceptions, the Scottish lochs have deposits which 
differ scarcely at all from loch to loch. The great majority of the 
mainland lochs exist under closely similar conditions : they lie in 
a country of fairly uniform mineralogical aspect, are provided with 
an inflow and an outflow of soft peaty water, receive a large supply 
of vegetable refuse, and are remote from thickly populated districts. 
Consequently the floors of the various lochs tend to be carpeted with 
much the same kind of deposit, and it is possible to deal generally 
with the deposits as if they belonged to one huge lake. Only in 
certain island lochs on the one hand, and in small and comparatively 
stagnant lochs on the other, are local peculiarities developed, which 
will be referred to in due course. 
Scottish loch deposits in general may be classified into three 
main varieties, viz. : — 
(1) Sand or Grit. 
(2) Clay. 
(3) Brown Mud. 
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