^{note * page 207} Notely Convener.—Professor Geikie, in a recent paper published in the Transactions of the Glasgow Geological Society {vol. vi. p. 160) on the “Geology of Colonsay,” mentions, that in the neighbourhood of Schallasaig there is a “granitoid rock” containing felspar, “which sometimes shows a rosy flush.”

^{note * page 208} Note by Convener.—With reference to the granite boulders, which in most cases Mr Murray seems inclined to connect with the Schallasaig granite rocks, it should be kept in view that at Killoran (in the N. W. of Colonsay) there are, as Mr Murray states, “rocks of both red granite and grey granite, which rise in masses to the height of 200 feet. The grey is found as far east as Ballinahard. At the same place there is an exposure of a third granite, of a dark colour, resembling syenite. In the same neighbourhood the schist is much contorted and burnt; and at its junction with the granite there is a vein of quartz rock or quartzite.”

Professor Geikie, in his memoir on the “Geology of Colonsay,” already quoted confirms Mr Murray's statement, when he refers to “a crystalline rock which appears to be of igneous origin, a syenite consisting of pink felspar and dark green hornblende. It occurs near Skipness, in the north of Colonsay, in which district, the schistose and gneissose strata are much broken and confused.”

^{note * page 209} Note by Convener.—Can this be a pebble derived from the rocks in Killoran Bay, described by Professor Geikie as “a remarkable volcanic agglomerate—made up of the broken angular débris of the strata by which it is surrounded ?” (Page 160.)

^{note * page 212} Note by the Convener.—In the 6-inch Ordnance Survey map of Rum, two “gravel pits” are indicated as existing in the N.E. part of the island at a height of about 200 feut above the sea.

^{note * page 214} Note by the Convener.—The foregoing report on Eigg having been submitted to Professor Heddle, he wrote to the Convener that he had never visited Eigg, but that he was well acquainted with the rooks in Rum, Mull, and Skye. He states that there is no true granite in Rum; but that at the S. W. corner of the island there is a large mass of a “variety of syenite, something like grey granite”; and that this syenite, and also the angite rock of the island, are of the “same type as that of the Coolins in Skye, and of St Kilda.” He adds that this augite rock is so peculiar, that if the Eigg boulders came from any of the above-mentioned rocks in these islands, he might perhaps he able to recognise them, on getting chips from the boulders.

In consequence of this last remark by Professor Heddle, the Convener applied to Mr Macpherson, to endeavour to obtain chips of the larger boulders in Eigg. In the course of a few weeks about a dozen chips were obtained, and were sent to the Convener.

The Convener thereupon forwarded them to Professor Heddle, who, after a first cursory examination, wrote to the Convener as follows:—”None of the boulders (judging by the chips) are from any point I know. None are granitic. One is a micaceous syenite, with characteristic radiation structure in its felspar. There is a micaceous gneiss—I think a Tiree rock. The others are either highly metamorphosed grits, simulating granites, or gneissose rocks. All are so characteristic that their source is certain to be sooner or later discovered. The island should be visited, to note carefully the features of the ‘lie’ of each boulder.”

A few days afterwards Professor Heddle wrote to the Convener, that having again examined the chips he found that “they consist of highly metamorphosed grits of gneiss, and of syenite;—they are all of much greater age than any rocks described as occurring in Eigg”; and suggested that they might be submitted to Mr Archibald Geikie and also to Professor Judd, both of whom he knew were well acquainted with West Highland rocks.

The Convener accordingly transmitted the chips to Professor Judd, with a, request that if Mr Geikie was in London, he would have the goodness to show them to him.

The Convener has received a note from Professor Judd stating that Mr Geikie and he had looked at the specimens, and he fixes on one which he says “I take for Torridon Sandstone. It is an Arkose, which Mr Geikie thinks may have come from the Torridon group;—but that it reminds him most of some parts of the Old Red Sandstone. None of the boulders are at all like any of the volcanic masses of the Inner Hebrides.”

“All the boulders, we both agree, may have come from the great gneiss masses of the central Highlands, and they do not appear to belong to the old Lewisian or Laurentian series. Mr Geikie adds, ‘I do not think anybody could venture to fix their source more precisely'; and in this I quite agree with him

Mr Geikie, in his account of the Geology of Eigg, adverts to the channe of an ancient river, in which he detected “pieces of red sandstone ‘of Cambrian derivation’—which make it clear that the higher grounds from which they were borne could not have lain to the S. or E., but to the N. W. or North.” From fragments of white sandstone (also found by him), he says, “We may with some probability infer, that the course of the stream (which brought them came from the north, where the great white oolite sandstones rise to the surface.”—Lond. Geol. Soc., vol. xxvii. p. 309.