the stone ball may have come, and most probably came, from some part of that district. Mr Peach mentions in his letters, quoted in the Report of the Committee, that similar concretionary balls occur in sandstone rocks near Burntisland, and suggests that the ball in question came from that quarter. In that case, the direction of transport would be from about due N. If the stone came from near South Queensferry, the direction would be from W.N.W., which last would be more in accordance with the evidence of direction indicated by many other data.

Assuming, then, as most probable, that the large stone ball, as well as the small metallic ball found in the Leith boulder clay, came from parent rocks, situated to the westward, the next question will be, by what agency were they transported?

Mr Peach, in his letter, apparently assumes, as matter of course, that these balls were transported by the agency of ice. But "ice” in what form?-land-ice, or sea-ice?

If the metallic boulder came from Campsie, the distance over which it travelled to Leith could not have been less than 30 miles; and as the Campsie coal strata are only about 150 feet above the present sea-level, there would not be gradient sufficient for a glacier either to carry on its surface, or to push before it, debris of rocks from Campsie to Leith. Moreover, Leith is not at or near the mouth of any valley which could create or guide a glacier from the west of Scotland.

But there are in the Campsie and Kilsyth districts marks of various kinds, indicating the action of a deep-sea current. These marks it is proper to notice, as having an important bearing on the general question of boulder transport.

Mr John Young of Glasgow, in the year 1868, wrote an instructive paper in the "Transactions of the Glasgow Geological Society," on the geology of Campsie. He says (page 14)-"There are few localities in the central district of Scotland, where such an extent of polished and striated rock surface is to be seen, as along the flat summits of the south hill of Campsie. The striæ vary in their direction from a few points north of west to south of west, according to the deflection of the ground;—many tracts of the sandstone rock, still showing the channelled markings in great perfection," at about 600 feet above the sea.

Mr Young then refers to the Strathblane Valley, which lies between the north and south hills of Campsie, and to the appearances indicating that it had been "swept by powerful currents of water, which have helped to produce those inequalities of surface seen along the outer margin of the tracts now occupied by the rivers Kelvin and Glazert. It was during the period when Scotland sat several hundred feet lower in the sea than it does at present, and when the valley of the Kelvin existed as a deep sound connecting the German and Atlantic Oceans, that those great beds of stratified sand and gravel were deposited which we now see filling up the Strath (as near the village of Torrance) to more than 100 feet above the level of the river. At other points along its course, similar deposits exist to more than 100 feet below the present sea-level. This shows that a very deep sound or valley must have originally extended across Scotland, previous to the glacial period, in this parti cular direction. A depression of the land to the extent of 350 feet would produce the following results :-The German and Atlantic Oceans would be united by the valley of the Kelvin, also by the valley of the Leven, Loch Lomond, and onwards by the low ground near Kippen to the Forth at Stirling. A narrow sound through the Campsie valley would connect the two seas, as the water-shed at Ballagan Bridge is only 330 feet. The Campsie and Kilpatrick hills would then form two islands, and the valleys of the Carron and the Endrick would be estuaries or arms of the sea. It is only by assuming conditions such as these, that we can hope to explain the superficial sedimentary deposits" (page 16).

In the year 1871, in company with Mr Young, I had an opportunity of visiting the Campsie district, and from my note-book I make the following extracts :

a. On Craigend moor, at about 450 feet above the sea, situated two miles west of Strathblane, I found the sandstone rock presenting extensive sheets of smoothed horizontal surface, evidently ground down by friction, and presenting occasional striæ, running in a direction S.E. by S. The rock had in some places imbedded in it quartz pebbles, standing up above the general surface. Being harder than the sandstone rock, these pebbles had been able to withstand the friction; but some of them showed marks of rubbing on their north-west sides.

b. At this place, looking towards the N.W.-viz., in the direction of Loch Lomond-an opening between the hills, which are apparently about 1000 feet high, was discernible; this opening being about 1 mile wide.

c. At four other places on Craigend moor, from 500 to 600 feet above the sea, two to three miles apart, there were striations on the rocks, pointing repectively S.E. by S., S.E. § S., S.E. by S., and S.S.E.

At all these places the direction was seen to pass through the opening between the hills above referred to, indicating that the agent, whatever it was, which produced the striations might have come, and probably came, by that opening.

d. On this same moor (forming an extensive plateau of about 6 miles long by about 3 miles wide) I had pointed out to me by Mr Young several boulders in different places.

Two were of trap, from the Kilpatrick hills, situated some miles to the W.N.W., and at a height of 570 feet above the sea. In circumference, each boulder measured 27 feet, and, so far as not buried in the drift on which they were lying, the height of one was 4 feet, of the other 6 feet.

Another boulder, well rounded, 500 feet above the sea, was of grey granite, weighing about 2 cwt., which Mr Young considered, from the size of its felspar crystals, to have come from Ben Awe, a mountain situated to the N.W., and distant about 50 miles.

There were several smaller boulders of old conglomerate transported, no doubt, from the well-known band of that rock which, running from Dumbarton, crosses Loch Lomond in a N.E. direction towards Aberfoyle.

e. In the valley of the Blane there are deep beds of sand formed, most probably, whilst the sea occupied the valley, and numerous well-rounded boulders of all descriptions. At Strathblane Railway Station there was a deep cutting of a sandbank, with several boulders in the sand, and one in such a position as to indicate that it had fallen from some raft which had been conveying it, as it was sticking with its narrowest point downmost.*

f. It was remarked to me by Mr Young, that whilst boulders,

See a diagram of this sandbank and boulder in a little book, published by Edmonston & Douglas in 1871, called "Estuary of the Forth."

gravel, and beds of sand are abundant in the valleys of Strathblane and Campsie, he had never found any marks of grinding or striation on the rocks in these valleys. These effects seemed to have been produced at levels higher than 400 feet above the sea.

On another occasion, when geologising on the Campsie hills, above Glorat, situated 3 miles to the east of Campsie, and at a height of 800 feet above the sea, I found the sandstone rock striated, in a direction due E. and W. On the Kilsyth hills, a few miles still farther east, and at a height of 1200 feet above the sea, the striations on the rocks were seen to be E. and W.

g. One other fact observed was the immense accumulation of boulders of all kinds at Croyhill, a knoll of trap, at the summit level betweeen the firths of Clyde and Forth-viz., about 160 feet above sea-level. As some of these boulders were of "old conglomerate," they afford additional evidence of an agency which brought them from the westward.*

h. In addition to these facts, notice may be taken of two boulders reported to the Committee by Mr Jack of the Geological Survey. One is of mica slate, weighing about 6 tons, on the Kilsyth hills, at 1260 feet above the sea, the parent rock of which Mr Jack supposes to be situated about 15 miles to the north. The other is of conglomerate, weighing about 7 tons, on the north hill of Campsie, at 1803 feet above the sea, with its longer axis W. 20° N. Its parent rock is supposed by Mr Jack to be to N.W. (First Report of Committee, p. 51.)

Now what do all these facts prove? They prove that an agent of some kind or other moved over this district, having a depth of at least 1800 feet, and covering a great breadth of country; and that, whilst this agent was moving, the rocks over which it passed were ground down and rutted and striated; large boulders, at a high level, were carried forward, and boulders at a low level were pushed in a similar direction.

The valley at worked, seems to

There is an additional fact deserving notice. Lennoxtown, where the pyrites coal strata are have at one time been filled up by these strata. These strata now, however, exist only on each side of the valley. Some agent has scooped them away, whereby the present valley was excavated; and it is

"Estuary of the Forth," p. 95.

possible that the balls found in the Leith boulder clay form a portion of the debris of these pyrites strata so broken up.

What agent can fit into all these conditions so well, as a sea current loaded with ice?

On this theory, it is intelligible why the rocks along the moors of Craigend and Craigmaddie, stretching for 5 or 6 miles in a direction S.E. and S.S.E., at a level of from 500 to 700 feet above the sea, should show more effects of grinding and striation than the rocks at a lower level. Had a glacier been the agent, the grinding would have been chiefly at the lowest, not at the highest levels.

The subjoined plan and section of Campsie hills and valley will make the foregoing explanations more intelligible. The plan is copied from a published map by Johnston. The section has been Ground Plan of Campsie Valley.

A, Pyrites coal strata, out-crop of.

B, Craigend Moor, 450 feet.

C, Craigmaddie Moor, 700 feet.

D, Boulder and striated rocks at Croyhill.

K, Kilsyth coal strata.

Boulders shown by black dotts.

Striæ on rocks by arrows.

FAE, Line of section across Campsie Valley.

kindly drawn for me by Mr John Young of Glasgow, who is thoroughly well acquainted with the geology of the district. In his letter sending the section, Mr Young says "The Campsie coal and limestone is at present worked on the flank of the north hill, as well as in the mine which you saw in the south hill. The valley