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water, or by both, it is difficult to say. Their height above the sea is about 780 feet. On the hills, on each side of the railway, there are traces of horizontal lines on the detritus, which deserve better observation than could be given from the railway carriage.

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1. On Sheriffmuir, 3 miles from Bridge of Allan, near Blackford, there is said to be a large boulder, called Wallace's Putting Stone.

NORTHUMBERLAND.

It was intended that only Scotch boulders should be inquired after by the Committee; but it is not irrelevant to notice a boulder which, though now in England, was probably transported from a Scotch mountain.

In Chillingham Park, the seat of the Earl of Tankerville, near Alnwick, there are several small boulders of granite. The rocks of the immediate neighbourhood are carboniferous sandstones and limestones. The nearest point for granite is the "Big Cheviot," eight miles to the W.N. W., and reaching a height of about 1800 feet above the sea. The largest boulder is 3 feet 2 in length, 2 feet

4 in width, and 2 feet high. It is round in shape, and about 400 feet above the sea.

Several valleys and ridges of hills lie between Chillingham and the Big Cheviot, across which the boulder must have been transported to reach its present site.

Remarks by DAVID MILNE HOME, LL.D., Convener of the

Society's Boulder Committee, on presenting the Committee's Fourth Report at a Meeting of the Society, 20th May 1878.

1. In presenting a Fourth Report from the Society's Committee on Boulders, I may be allowed, first, to refer to the main object for which the Committee was appointed.

It was to collect data which might help towards a solution of the problem, by what agency boulders in Scotland had been transported from the parent rocks to the positions they now occupy.

The Transactions of the Society contain numerous papers by eminent geologists on this question.

At a very early period, Sir James Hall, when he drew attention to many large boulders, and also to the remarkable appearances called "crag and tail" in the midland districts of Scotland, ascribed both sets of phenomena to the agency of great bodies of water, which had passed over the country from west to east.

At a later period (about the year 1842), Agassiz and Dr Buckland started the idea, that as in Switzerland, glaciers had been the means of carrying masses of rock from the Alps across the valley of Geneva to the Jura mountains, so there might in former days have been glaciers in Scotland producing similar effects.

More recently a third theory was started,-that if the sea stood several hundred feet above its present level, floating ice might have been the means of transporting the boulders, and carrying them great distances.

2. There being thus three different theories of transport, each supported by eminent geologists, the Committee has endeavoured to gather facts to ascertain which theory is the most probable, or whether any better can be suggested.

I do not presume to say that the information contained in this and

the previous Reports will yet allow the problem to be solved. But at all events it may be conceded that some new facts have been ascertained, which throw considerable light on the question.

I venture to indicate what appear to me to be several conclusions warranted, though in doing so I offer only my own opinion. Perhaps the Committee, after more information has been obtained, may be induced to consider whether they will pronounce on the various questions of interest which the subject presents.

I confine myself this evening to only a few points, and chiefly to illustrate what occurs in our last Report.

3. The boulders referred to in the Report may be divided into two classes.

First, There are boulders which, from the nature of the rock composing them, are so soft and friable, that they could have been transported only short distances-such as sandstone, coal, and shale. In the Report, examples are given of such boulders, from Berwickshire and Mid-Lothian.

The second class of boulders, namely, such as are ascertained to have come from remote quarters, are composed of rocks, hard, compact, and homogeneous in composition; such as basalt, greenstone, granite, felspar, quartz, grey wacke, and old conglomerate.

Boulders of these rocks have been found even as far as 80 or 100 miles from the parent rocks; and, generally speaking, they are well rounded, presenting evidence of enormous friction undergone whilst in transitu; and even in some cases acquiring almost a spherical shape. Specimens of small spherical boulders are now on the Society's

table.

There are, however, exceptions to the rule that boulders of hard compact rocks are generally well rounded. Cases of boulders of these hard rocks occur extremely angular in shape. Examples are shown in this Report, by the lithographs appended to it, and in previous Reports. These angular boulders are almost invariably at high levels, on the sides of mountains or near their tops. The well rounded boulders are generally at low levels, and most frequently imbedded in boulder clay.

4. It will be asked, whether the Committee has in any case ascertained the parent rock from which a boulder has come.

VOL. IX.

4 Y

The answer is, that the Committee can in no case point out the particular rock from which a boulder had originally been broken off. All they can affirm is, that in several cases they have ascertained the district or quarter from which the boulder must have come.

(1.) For example, in Berwickshire, as will be seen from this last Report and the second Report, particular hills are specified from which boulders must have come. The direction in which they came, and the number of miles traversed, are therefore in these cases matter of certainty. In every case over the whole county of Berwick, from its lowest to its highest level, the direction of transport is from points between W. and N.W. (magn.)

The same is the case in Mid-Lothian. The sandstone boulders at Craiglockhart are shown to have most probably come from rocks situated a few miles to the N. W. The quartz and other hard rock boulders at the same place, as also at Liberton and at Leith, in like manner probably came from points between W. and N.W.

(2.) The two remarkable spherical balls of marcasite, found in the boulder clay at Leith and mentioned in this Report, must in like manner have come from the westward. A presumption to that effect arises, from the mere fact that they are in the same bed of clay which contains granite and other Highland rocks. But there

is more than presumption. Mr Peach having indicated where pyrites balls might be found in situ, viz., at Campsie and Kilsyth, I went to Campsie last week, and on inquiry was shown some thin strata of coal, abounding in nodules of pyrites, several of the nodules so large as to weigh half a cwt. The coal is worked for burning limestone. It is too full of sulphur for domestic use. Specimens of this coal, with the pyrites nodules which I obtained on the spot, are now on the table of the Society.

Kilsyth I did not visit, because the overseer at Campsie told me that he had worked at Kilsyth, and that there were pyrites nodules in the coal strata there, similar to those at Campsie, but of rather smaller size.

Some of the nodules which I obtained at Campsie I submitted to Professor Crum Brown, that he might examine them to see whether they contained "marcasite." He has reported to me as follows:"These nodules have a specific gravity of 412, and consist of iron, sulphur, and coaly matter in the following proportions :

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Deducting the coaly matter, the iron and sulphur would be in the proportions in which they are generally found in 'marcasite,' viz.,

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'Iron, 45.61; and Sulphur, 54.29."

As regards chemical compositions, therefore, the small metallic boulder may be considered as exactly agreeing with the nodules found in the Campsie coal strata. This agreement in composition. affords a strong ground for inferring that the boulder had been transported from Campsie, or from Kilsyth, as suggested by Mr Peach.

With regard to the larger spherical ball found in the same bed of boulder clay at Leith, I am now able also to indicate the part of the country from which it was probably transported. Mr Hutchison of Carlowrie, happening to see this stone ball, informed me of two quarries in Linlithgowshire where concretions resembling it were in abundance. These quarries are near Humbie and Dalmeny, situated from nine to ten miles due west from Edinburgh. Mr Hutchison having sent to me several of these concretions, I was induced to visit Dalmeny Quarry. I found in the sandstone rock there, numerous concretions of all sizes up to nearly 4 feet in diameter. Humbie Quarry I did not visit, as the working of it had been given up, and it was full of water. A concretion from

this last mentioned quarry, sent to me by Mr Hutchison, Professor Crum Brown has examined, with the following result:-“ It weighs 171 lbs. It consists externally of a thin shell of sandstone, and internally of a mixture of quartz and marcasite, closely resembling the substance of the large ball from Leith. The mean specific gravity of the ball was 3:49."

There is thus a sufficient similarity of composition in regard to the stone ball and the Humbie concretions, to make it exceedingly probable that these Humbie sandstone rocks supplied the stone ball. I do not say that Humbie Quarry was the exact spot from which the stone ball found at Leith actually came. The sandstone strata which occur at Humbie and Dalmeny of course crop out elsewhere in the district near South Queensferry; all that can be said is, that

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