other places in the West Highlands where there are fresh-water lakes close to the sea, formed in like manner.

With regard to the boulders, it occurred to the Convener, judging from their locality and their position, that they had probably been floated up Loch Creran, and been then stopped in their further progress by the contraction of the valley and the higher level of the land.

But if they were floated up Loch Creran, from what quarter did they come? It was natural to look to places facing the mouth of Loch Creran, if in these places there were mountains composed of rocks similar in composition to the boulders. The island of Mull, situated to the W.S.W. of Loch Creran, seemed therefore to be one locality which might have supplied the boulders, as from Mr Judd's instructive paper on Mull,* describing numerous varieties of granite in the mountains of that island, it appeared likely that rocks of the same character as the Fasnacloich boulders existed there. With the view of testing this idea, the Convener sent specimens of the boulders to Professor Judd, who he heard had, during the past autumn, spent three months among the Mull mountains, and asked him to state whether he recognised the rock composing these boulders as being identical with, or at all events similar to, any of the Mull rocks? Professor Judd was so obliging as to respond to the application.

With the Fasnacloich specimens, there went to Professor Judd specimens of the rock composing two very large boulders on the shore at Appin, which rock the Convener found on examination to be the same as that of the Fasnacloich boulders. These Appin boulders lie on upturned blue clay slate rocks. Their shape indicated that they had undergone great friction, in consequence probably of being rolled over the sea-bottom by icebergs floating through what was then a sea strait, but now the Linnhe Loch, and the chain of lakes forming the Caledonian Canal. Sketches of these Appin boulders were taken. The largest is 15 x 11 x 10 feet. Both boulders are well rounded at the angles.

Professor Judd's Report is in the following terms :

"Appin Boulders, No. 1.-This rock is not a granite, but a rock of basic composition. It appears to be a gabbro with some black mica. It is very similar in character to the gabbro of Skye, Rum, Ardna* See "Geolog. Society's Trans."

murchan, and Mull, which are described in my paper. I think there is no room to doubt it was derived from one of these localities —the rock is so peculiar and well characterised.

"Fasnacloich Boulders, Nos. 2, 3, 4, are very ordinary gabbros, such.as form great mountain masses in Skye, Ardnamurchan, and Mull. These rocks are of a striking character, and differ from any which I know of on the mainland. I think it is certain, they were

derived from the Western Isles."

Professor Judd, in his paper on the ancient volcanoes of Mull, Skye, and Ardnamurchan, refers to proofs that these volcanoes reached a greater height above the sea-level than any of the existing Scotch mountains, perhaps even to the height of 14,500 feet, and that "denudation" had acted to an enormous extent in breaking up the old volcanic rocks and lowering their height. Professor Judd does not particularly specify the nature of the denuding agent which he supposed produced this effect. But if the sea with ice floating in it, at a height of say 2000 or 3000 feet above the present level, be allowed to be a denuding agent, it is easy to see how the boulders of Appin and Fasnacloich, if derived from Mull or Ardnamurchan, might have reached their present positions.

The distance of Appin and Fasnacloich from Mull and Ardnamurchan is about 30 miles. The intervening sea has in some The island of Lismore, which is

places a depth of 100 fathoms. in this part of the Linnhe Loch, at one spot only reaches a height of 420 feet. A sea current flowing across Mull and Ardnamurchan, towards and through what is now known as "Glen na Albin," with mountains on each side of the Glen reaching to 2000 feet above the present sea-level, might, by floating ice, have carried boulders and lodged them in lateral valleys, such as Loch Creran.

11. Crinan Canal.-At the summit level, about half-way between the two extremes, there is a large accumulation of boulders, chiefly angular in shape. On the west side of the canal at the "locks," a body of rock stands up, whose surfaces facing the north present marks of abrasion as if caused by some body or bodies passing over from the north. On the south side of this rocky knoll, lie a number of boulders which, if they came from the north on floating ice, may have been projected over the knoll by its intercepting the ice

* Quarterly Journal of the Geological Society for August 1874, page 259.

in its farther progress through this kyle or sea channel. One of the largest of the boulders is lying with its longer axis N. and S., or parallel with the general axis of the valley at this point. These conditions would be met by the sea standing at a height of from 140 to 150 feet above the present level. On both sides of the valley here there are horizontal lines traceable at that height, as if made by the sea.

12. Island of Islay.-The Convener, in August 1877, paid a visit to this island, for the purpose chiefly of examining the famed raised sea beaches on the adjoining island of Jura, and also of inspecting some boulders of which notice had been sent to him.

(1.) On the farm of Lossit, about three miles south of Port Askaig, there are four or five boulders of large size. Only two were seen.

One of these, 13 x 8 x 8 feet, is a composite rock containing crystals of quartz, augite, and hornblende. The stone is extremely hard; it was with much difficulty that a small specimen was detached. The boulder was resting on a bed of bright yellow clay, apparently a sediment of deep water. The rocks of the district are a slaty schist. On inquiry, it was surmised that rock of a similar kind existed near Kildalton, about 20 miles to the S.E. But doubt exists on this point.

The other boulder, scarcely so large as the foregoing, resembled a compact Silurian rock, containing numerous crystals of a whitish felspar.

There was nothing to indicate how or from what quarter these boulders came. Their height above the sea was about 300 feet.

(2.) On the farm of Arnahoo, about three miles north of Port Askaig, and 228 feet above the sea, a boulder stands conspicuously on the summit of a hill in a position most precarious (fig. 8, Plate III.). The rock composing the boulder is a hard porphyry, quite different from the rocks of the hill on which it rests. Its height above the sea is 228 feet, and the hill itself is about 300 yards from the sea, towards which it slopes very steeply.

The boulder is not absolutely on the highest peak of the hill, but a few feet below the peak, and on the slope which faces north by east (magn.). The only way in which the boulder could have stuck on this slope was by its coming right against it, and being let down on it gently, i.e., without falling from a height. It

must have come in a direction from N. by E. If floating ice brought it and no other way is here conceivable-from the south, the boulder could not have reached its present position. It would have stuck on the south side of the hill. It could not have reached its position by a somersault over the hill top, for the impetus acquired by its fall would have projected it down the hill altogether.

As bearing on the direction from which this boulder may have come, it is proper to add that towards the north-west there is a range of hills, apparently much higher than 300 feet, whilst towards the north and north-east it is open sea, and the island of Mull is in that direction.

(3.) On the farm of Persibus (occupied by Mr Rounsfell), about three miles S. W. of Port Askaig, four or five boulders, well rounded, occur, and were seen. They are all of a hard porphyritic rock, differing from any of the Islay rocks. Their height above the sea was found to be about 228 feet.

With regard to the probable line of transport to their positions, it may be noticed that towards N. by E. there is an opening or depressed part of the country, through which the boulders might. have been floated to their sites.

Mr Rounsfell pointed out a very large boulder situated on a hill slope to the north, about two miles distant, which, however, the Convener was unable to visit. But Mr Ballingall, factor on the Islay estate, has had the kindness to examine the boulder, at the request of the Convener, and he reports as follows:-"Girth, 333 feet; height, 11 feet; length, 12 feet; breadth, 18 feet. It lies on clay slate rocks, and is all exposed to view. Its thickest end faces S.W. Its height above the sea is 410 feet." Mr Ballingall has sent with his letter a small chip of the boulder. It proves to be an igneous rock, with much hornblende. It has probably come from some northern region. The weight of the boulder Mr Ballingal estimates at 25 tons.

(4.) On the south side of the high road between Bridgend and Port Helen a boulder rests at the foot of a low hill which faces about due north. The boulder is tolerably well rounded, and about 7 feet in diameter. It is a stranger to this district. Most probably it came from the north like the rest, and was in its farther progress intercepted by the hill at the base of which it lies. Its height above the sea is about 50 feet. (See fig. 10, Plate III.)

(5.) On the west coast of Islay, in the parish of Kilcheran,

there are porphyritic boulders lying on the blue slate rocks, and so situated as to make it clear, that they have been brought and lodged there by some agency from the N.W.

Below the old parish church of Kilcheran a small stream joins the sea through a valley in a direction W.N.W. (magn.). The rocks on the south bank of the stream are ground down and striated in such a way as to show that some force has passed obliquely across the valley from N.W.

In regard to these Islay boulders, it is very apparent that they have all come from the north-some of them very probably from Mull. It is also rather remarkable that the largest should occupy sites very nearly on the same level, viz., 228 feet above the sea, a circumstance suggesting the same means of transport. As bearing on this last point, it may be observed, that on various parts of the Scotch coasts there are traces of old sea-beaches, at heights between 250 and 500 feet above the present sea-level.

13. On the Peninsula situated between the Firth of Clyde (on the east side), and Loch Striven (on the west side), there are several boulders of some interest.

(1.) At Dunoon and Kirn there are boulders of a micaceous sandstone rock, all well rounded, lying on the edges of the blue slate rocks which form the beach. One has had painted on it the words "Jim Crow," being 15 x 8 x 6 feet; another, the words "John Bull," 15 x 12 x 6 feet.

It was stated to the Convener by a local correspondent, that rock of the same nature as in these boulders occurs in the Holy Loch, situated about a mile to the north-west.

Two of the boulders on this part of the beach are so fixed as to indicate from what quarter they must have come into their present position, viz., from the North. Sketches of these were taken.

(2.) Along the shore towards Innellan there are numerous boulders differing from the rocks on which they lie. Some of these rocks show surfaces smoothed and striated, the striæ running north-east and south-west-a direction parallel with the general line of coast. Some local agency has, therefore, probably been at work here.

(3.) On the east shore of Loch Striven lies the large, well-rounded boulder, called "Craig na Calleach," or "Stone of the Witch"-the legend being that in former times, the witches inhabiting both