Reservoir, at an elevation of 900 feet (H 5). It is a stiff reddish clay, full of well rubbed and scratched stones, and differing in no way from the boulder clay of the lower districts. The other locality is about three miles to the S. W. of this, in the same line of valley between the hills, at an elevation of about 1100 feet. It is of the same character as the last, but is covered by a great deposit of gravel and boulders, which extends across the broad valley between Hare Hill and South Black Hill (H. 6).

Another large deposit of gravel and boulders is at the mouth of the broad valley in which the Bonally Pond lies, at an elevation also of 1100 feet above the sea. This deposit encloses some very large boulders of greenstone (H. 6).

III.

The Convener appends to the foregoing Notes by Messrs Somervail and Henderson, the References by the late Charles Maclaren, by Professor Geikie, and Mr Jas. Croll, to Striæ and Boulders on the Pentlands, as the localities are embraced in the same map.

1. Mr M'Laren, in his "Geology of Fife and the Lothians," states :

(1.) "There are few opportunities of observing 'groovings' on the Pentland Hills. I noticed them, however, at Westwater of Dunsyre, on the top of a thick bed of hard sandstone, from which 12 or 14 feet of alluvium had been removed. The dressings pointed exactly east and west; and the evidence was the more satisfactory, as the direction of the stream on whose bank the rock was situated, and of the valley in which the stream flowed, was south and north. They were very distinct, the larger groovings being about 1 inch broad, andths of an inch deep. The locality must be 800 or 900 feet above the sea" (page 294).

(2.) Travelled blocks are important in two respects:—first, as indicating the action of currents or other transporting agents no longer operating; and next, as illustrating changes which have taken place subsequently to their deposition in the spots where we find

them.

a. "In the Pentlands there is a boulder of mica slate, weighing 8 or 10 tons, on the east end of Hare Hill (see plan annexed, M. 1). It reposes on the surface of the west side of the glen leading north from Habbies How to Bavelaw, on a declivity about 80 feet above the bottom. The nearest spot from which this mass could be derived is the portion of the Grampians about Loch Vennacher or Loch Earn, 50 miles distant" (page 301).

Further, this block tells us that the surface of the hills where it now rests must have been in a different condition when it was deposited. It lies on the side of a declivity, where a large stone, either hurried hither by a current, or dropped from an iceberg, would not stop, but roll down to the bottom of the valley. The reasonable inference is, that the valley between Hare Hill and North Black Hill was then filled with "materials which have since been washed away" (p. 302).

b. Half a mile south from this, three greenstone boulders of 2 or 3 tons weight each are lying on the edge of a precipice, about 200 feet above South Burn. (See plan, M. 2.)

These have certainly travelled some miles, and the bed of clay seen below them is no doubt a remnant of that which then filled up the ravine, and prevented them descending to the bottom.

c. On the east end of West North Black Hill there is a sandstone boulder of 8 tons weight. (See plan, M 3.)

This block may not have travelled far. But it rests on a surface as steep as the roof of a house (inclined both above and below at 45°), and about 400 feet above the bottom of the valley.

It is impossible that it could be dropped here, or brought to the spot by a current, without descending to the bottom, unless sustained in its place by matter since removed.

This single block informs us that the ravine about 100 yards wide at the surface of the marsh, which separates Black Hill from Beild Hill, must then have been filled up with alluvial matter to the height of 400 feet at least above its present bottom, which is probably 50 feet above the true bottom in the rock (page 302).

d. On the south declivity of Harbour Hill, about 300 feet above the level of the Compensation Pond, there is a very large boulder of greenstone weighing 12 or 14 tons. (See plan, M. 4.)

The surface it rests on is not steep.

But the boulder must have

travelled many miles; for there is no greenstone of the kind in the hills, and none near them, except in situations 500 or 600 feet lower.

This block has probably been transported in the same manner as the mass of mica slate (a above).

e. The same remarks apply to a greenstone boulder lying half a mile N.W. of Logan House, on the south side of West Black Hill, about 1400 feet above the sea. It is of 12 or 14 tons weight. (See plan, M. 5.)

There are many others in elevated situations of 3 or 4 tons weight.

The substance is generally greenstone, the least brittle probably of all rocks, and of course the best fitted to resist fracture. all the blocks have their angles rounded off.

Nearly

f. On the banks of Eight Mile Burn, in the low ground, there is a mass of alluvium about 100 feet thick, containing hundreds of trap boulders of all sizes up to 10 tons weight. It consists of two beds, the older, a blue unctuous clay, the newer a red clay. The large blocks are chiefly in the latter.

There are many similar travelled blocks in the burn flowing from the old Reservoir to Bonally, and probably in all the streams of these hills (page 303).

2. Professor Geikie, in his Memoir "On the Geology of the Neighbourhood of Edinburgh," published in 1861, observes (1) that "boulder-clay lies along the north-west flanks of the Pentlands, rising to a level of at least 1300 feet."

When the clay has been recently removed, we usually find the rock below polished, grooved, and scratched in a direction nearly E. and W., or E.S. E. and W.N.W. These markings even remain distinct on hard greenstones which have remained exposed to the weather for an indefinite period.

The parallelism of the striations throughout the present district shows that the floating ice must have moved in a pretty uniform direction; and that it was from the west is rendered clear by the striation of the western face of the hills, by the great depth of drift on their eastern sides, and by the fact that the transported boulders, when traceable to their parent rock, have been carried from west to east (page 126).

VOL X.

X

(2.) Of boulders which have undoubtedly been transported either from Cantyre or the Grampian Highlands, I may refer to the mass of mica slate about 8 or 10 tons, on the S. E. side of Hare Hill above Habbie's How, which was first noticed by Mr Maclaren.

(3.) On the other side of the valley, on the S. W. slope of North Black Hill, several smaller masses of white quartz rock occur, fully 1300 feet above the sea-level.

Masses of gneiss, mica-slate, and a hard metamorphic conglomerate, are found in tolerable abundance all over the district.

3. Mr Croll, in "Climate and Time," gives the following observations:

:

"On ascending Allermuir Hill (1617 feet), Mr Bennie and I found its summit ice-worn and striated. The striae were all in one uniform direction, nearly east and west. On examining them with a lens, we had no difficulty in determining that the ice which affected them came from the west, not from the east. On the summit of the hill we also found patches of boulder clay in hollow basins of the rock. At one spot it was upwards of a foot in depth, and rested on the ice-polished surface. Of 100 pebbles collected from the clay, just as they turned up, every one, with the exception of 3 or 4 composed of hard quartz, presented a flattened and iceworn surface, and 44 were distinctly striated. A number of these stones must have come from the Highlands to the north-west.

"On ascending Scald Law (1808 feet), 4 miles S. W. of Allermuir, we found in the debris covering its summit hundreds of transported stones of all sizes, from 1 to 18 inches in diameter " (pp. 441, 442).

2. Remarks on the Boulder Report by the Convener of the Committee, read (in the absence of Mr Milne Home, Convener), by Mr Ralph Richardson, Member of Committee.

This Report contains information applicable to three districts of country, namely

1. Pentland Hills.

2. Morayshire.

3. Islands of the West Coast, and

part of the Mainland.

1. PENTLAND HILLS.

The impression hitherto had been, that the boulders on these hills indicated a movement exclusively from the north-west; and there is no doubt that the mica slate boulders on these hills indicate such a direction; but Messrs Somervail & Henderson, in the notes contained in this Report, have discovered a separate movement from the west-south-west, by the occurrence of certain sandstone blocks, which they think can be traced to a particular hill or hills in the Pentland range. This point is so important, that it is hoped further inquiry may be made regarding it.

2. MORAYSHIRE.

The boulders in this country are described in a very interesting Report by Mr Jolly, Inverness, a member of the Committee. Mr Jolly's concluding paragraph deserves notice. He says, "None of these boulders are to the west of the points in situ where the parent rock is found-at least I have found none, and I speak from a pretty extensive knowledge of the district. What the transporting agent or agents were, whether glaciers, icebergs, icefloes, or water-currents, or one or more of these together, however interesting and important, it would be foreign to the purpose of the present paper to consider; but that these rocks were carried from their native sources, and scattered widely and numerously to the eastwards, over a large extent of country, cannot for a moment be doubted."

3. ISLANDS OF THE WEST COAst, and part of the Mainland.

It will be seen from the Report that my own personal survey last summer was chiefly among the islands, which, commencing with Iona at the south, stretches through the Western Hebrides to the north end of the Lewis, a distance of 120 or 130 miles. I selected these islands for two reasons:-1st. Because the boulders on them would be in their original undisturbed positions; 2d. Because one of the agencies by which transport of boulders has hitherto been most commonly explained, i.e., local glaciers, could hardly be adopted for these island boulders. The highest mountain in any of these islands does not exceed 2000 feet, and on most of the islands the height of the hills does not exceed 500 feet. Moreover, even in the