^{page 524 note *} I need hardly say, that the sections formed by the burns are transverse to the bedding of the boulder-clay; and, therefore, that the above measurements do not give the true depth of the deposit, but only the height of the sections.

^{page 525 note *} One is apt to mistake mere erosions of the boulder-clay for true basins in the basement rock, but where there has simply been an erosion, there is of course no such agreement as that spoken of between the contours of the surface of boulder-clay and the basement rock.

^{page 525 note †} I do not think this moraine has been noticed. It lies near the head of the glen, and rises to a height of 800 or 900 feet above the level of the sea. Where the glen contracts there are, on the south side, immense heaps of huge blocks of rock tumbled down in the wildest confusion,—the same appears on the north side of the valley, and all the valley bottom is obstructed by heaps of gravel and stones. The cup formed by this is about half a mile long, and above, on all sides, the hills rise perpendicularly to a height of 1100 or 1200 feet. These moraine masses extend down to the foot of Glen Dhu, more than half a mile, and in this glen, also, is some appearance of smaller moraines. In the lower part of the Glen Cloy moraine granite boulders become frequent.

^{page 526 note *} For list of these see end of paper.

^{page 534 note *} Just where the burn escapes from this basin, the section of the strata shown in twenty yards of the burn-course is most curious. Descending the burn, one first reaches the junction of the felstone porphyry and the underlying sandstone. The felstone porphyry crosses the burn to the N.N.W., and unconformably overlies the sandstone from which it is parted by a greenstone dyke. The sandstone is considerably hardened. A little lower down the burn the sandstone laps up on the back of a mass of the laminated felstone, the laminæ of which are parallel to the junction-line with the sandstone, but turn sharp round at an acute angle, where they abut against another greenstone dyke, which here occupies the opposite or left side of the burn, and which cuts through the sandstone from S.E. to N.W.

^{page 538 note *} I have repeatedly lain on the edge of such a bank, at the mouth of glacier rivers in Norway—particularly at the Skars Fjord glacier, where nothing but warps would hold us, the face of the bank on which our anchor lay being too steep to afford any hold. Our bows were almost grating on the shingle, while we had 70 fathoms under our stern, and 83 fathoms, with a fine mud bottom, at 100 yards distance. The surface water was filthily turbid, bitterly cold, perfectly fresh, and not above 8 or 9 feet deep, if so much; below was the clear salt water, sensibly warmer, and swarming with animal life, both fish and mollusks.

^{page 541 note *} Such jerks must of course be supposed considerable, since, if minute, the subsidence in this way would practically be slow and steady as in the other.

^{page 544 note *} I cannot let this paper go without expressing my obligations for much information and many suggestions to my friend Mr Geikie's valuable paper on the Phenomena of the Drift. I am gratified to agree with him on the land origin of the material which constitutes the boulder-clay, and on the subsidence of the land during the formation of the boulder-clay. On some other points, too, I think we are not very far from an agreement, though I fear we differ fundamentally on many of the most important.

^{page 544 note †} I only found one specimen of this species. The shells were partially crushed, but the two valves were united, and retained both epidermis and ligament. Mr Searles Wood, who was good enough to examine it for me, says it is one he does not recognise. Mr S. P. Woodward, who has also taken the trouble of looking at it, considers it an unusually large A. compressa of the variety striata. It is one-third larger than even the excessively large specimens of the species from the Red Crag, figured by Mr Searles Wood in his Bivalves of the Crag.—(Pal. Soc. Pub., vol. ii. p. 184, pl. 16, fig. 8, a and c.)