048 DR HUGH ROBERT MILL ON THE 



Loch Strivan runs N. by W., parallel to Loch Eck and Loch Goil for 9 miles, but, 

 unlike these basins, the width decreases uniformly from mouth to head. Its area is 5 

 square miles, or, including Rothesay Bay and part of the Bute Plateau, 12 square miles. 

 The hill slopes on both sides are unusually steep and unbroken, and scored to a 

 remarkable extent by the narrow gullies of torrents. The trough of deep water, which 

 has a maximum depth of 42 fathoms one-third of the distance from the head, runs for a 

 mile south of Strone Point, which marks the west side of the mouth. In this Loch 

 Strivan is unique, as the entrance is not crossed by a bar. If, however, we disregard the 

 shallow opening of the Kyles, the true mouth of Loch Strivan appears opening parallel 

 to that of the Holy Loch and of Loch Goil between Toward and Bogany Points. Then 

 the Bute Plateau would form the barrier, and the tongue of the Arran Basin running 

 northward between Bute and Cumbrae would be the natural continuation of the depres- 

 sion. Section 12, Plate VIII., illustrates this configuration. The land drainage area ex- 

 tends to 37 square miles. The volume of water present at low tide is 0*162 cubic sea 

 mile, corresponding to an average depth of \7\ fathoms, and a mean depth of 29^ 

 fathoms along the axis. The tidal rise adds 0*014 cubic sea mile of water. 



The Kyles of Bute, separating Bute from Cowal, may be viewed as made up of three 

 parts. The east channel runs N.W. by W. for 5| miles from Ardmaleish Point in Bute, 

 with an average breadth of two-thirds of a mile between hills of considerable height and 

 steep slope. The depth is about 23 fathoms in the centre and diminishes toward the 

 northern end, where the channel is broken by the Burnt Islands into several shallow 

 passages. The north channel, of slightly greater width, with steeper and loftier walls on 

 the north or Cowal side, runs 2^ miles in a S.W. direction, and finally the west channel 

 runs S.S.E. for 5 miles into Inchmarnoch Water, and increases to a width of 2\ miles off 

 Ardlamont Point. The shore on each side becomes low, but the depth in the centre of 

 the channel increases steadily, merging into the deep water of the Arran Basin. 



Loch Ridun, running for 2f miles N. from the Burnt Islands at the acute angle 

 between the east and north channels of the Kyles, has a breadth of half a mile, and is 

 inclosed on both sides by cliffy hills of exceptional ruggedness and steepness. The loch 

 shoals uniformly half the way up, but the upper half is tidal, at low water forming a sandy 

 flat, across which the long Ruel River winds sluggishly. Glendaruel, a long and remark- 

 able valley parallel to Loch Fyne, is flat but steeply walled, and the river, which has so 

 thoroughly silted up Loch Ridun, is reinforced by countless mountain burns. The water 

 surface of Loch Ridun and the Kyles taken together is 10 square miles, and the area of 

 land drainage — most of it into the loch — is 67 square miles. The volume of water con- 

 tained in this system is about 0*097 cubic sea mile at low water, with an addition of 0*012 at 

 high tide. The mean low-tide depth is \2\ fathoms, and the mean axial depth 21 fathoms. 



Loch Fyne (Upper Loch Fyne), with an area of 28 square miles, is the most 

 interesting, and in many respects most typical of all the divisions of the Sea Area. As 

 the conditions of its temperature, salinity, and the singular nature of its fauna have been 

 worked out in more detail than is the case for other regions considered, it is necessary to 



