
CRUISE IN LOCH FYNE, JUNE, 1899. 375 
but it has more probably been formed by the action of tides . 
and currents. 
In the Vew Statistical Account (1844) the minister of the parish 
of Glassary writes—“ There is a remarkable bank formed of sand 
and debris from the hills on each side of Lochfyne at Ottar. 
This bank, with the other depositions by which the bed of Loch- 
fyne must necessarily be raised in its level from year to year by 
the disintegration of rocks, the carrying away of banks, etc., may 
possibly effect great changes upon the character of the loch above 
Ottar on some future day, by obstructing the ingress of the tide 
and converting the upper portion into a fresh-water lake with its 
river entering the sea; and would it not be worthy of the heritors 
to take some measure of making such observations on each side 
of the Ottar, as may be necessary to ascertain the rate of increase 
of this bank, if any ; whether there be a tendency to the forma- 
tion of a similar bank down on the north side, etc. ?” 
The run of the current is, we expect, sufficient to keep the 
channel open, but such observations would be of considerable 
scientific interest. 
The geological structure of the rocks in the neighbourhood of 
Loch Fyne is very complex. No organic remains have yet been 
found in them. Their age is not known; they may be Lower 
Silurian, Cambrian, or even Pre-Cambrian. Those in the Cowal 
district have been described in the memoir of the Geological 
Survey, already referred to, published in 1897. 
Most of the rocks are evidently of sedimentary origin, but 
since they were deposited in the seas or lakes of remote 
times they have undergone great changes, whereby their original 
structure has been completely altered, and they now present a 
highly crystalline appearance. Even the igneous rocks appar- 
ently intruded into them, and if so, newer than the sedimentary 
rocks, have been metamorphosed, with the exception of the mica- 
traps, lamprophyres, and dykes of probably late Carboniferous 
and Tertiary ages. This metamorphism has perhaps been caused 
by earth movements on a large scale, whereby the strata forming 
the crust of the earth have been folded, twisted, and crumpled. 
These movements have occurred more than once, and the 
repeated foldings have produced new structures in the rocks. 
The original lines of bedding have in many cases been almost or 
