Lower Canada, and therefore speaks with authority on these points. The vexed question of the origin of the Boulder Drift, occupies the chief part of the chapter he devotes to the general subject. He differs from some of the highest authorities who have written on it, such as Agassiz, Dana, Ramsay, Jukes and Geikie, who believe that it results from the action of ice moving over an inclined surface in the manner of modern glaciers.

We cannot help thinking that Dr. Dawson's judgment is here again at fault, in at all introducing this discussion into such a work as the present. Were it an ordinary text-book, a short statement of the arguments on both sides might be suitable. Or were it a volume devoted to the general principles of the science, a more full discussion might be admissible. But in a work on local geology one would above all things expect, an account of the phenomena characteristic of the formation, which the country presents. Instead of this, Dr. Dawson has given us a philosophical disquisition, on what he himself admits to be, "one of the most vexed questions of modern geology," adopting in the most exclusive and one-sided manner, the old theory of ocean-currents and ice-bergs.

As he has seen fit to adopt this course, it may be well, by way of bringing these remarks to a close, to look, with him, at one or two of the points on which he touches.

This is his theory of the origin of the drift, "Let us suppose," he says, "the surface of the land, while its projecting rocks were still uncovered by surface deposits, exposed for many successive centuries to the action of alternate frosts and thaws, the whole of untravelled drift might have been accumulated on its surface. Let it be submerged until its hill-tops should become islands or reefs of rocks, in a sea loaded in winter and spring with drift ice, floated along by currents, which, like the present Arctic current, would set from N. E. to S. W. with various modifications produced by local causes. We have, in these causes, ample means for accounting for the whole of the appearances, including the travelled blocks and the scratched and polished rocksurfaces."

Were this theory true to fact, we should find the drift arranged in two distinct strata, in accordance with the change in the operating cause. We should have, first and lowest, the "unstratified drift," composed exclusively of the waste of the rocks underlying it, as produced by "the action of alternate frosts and thaws." Above this we should have, what should be distinguished as the "travelled drift," accumulated by ice-bergs and ocean currents, and mingled largely with foreign boulders carried from a greater or less distance. Now, it is notorious that this is not the case. There is not the remotest sign of anything like stratification characteristic of this formation. And this could not have been so, if the action of the sea were the chief cause concerned in its production. Besides, foreign boulders are mingled with the clay and sand throughout it. They are as numerous near the base as near the surface. In short they are irregularly and indefinitely scattered throughout it without any apparent order or arrangement. And, further, did the invasion of the land by this supposed ocean

current, loaded with ice, not take place until after the whole of the "untravelled drift" had accumulated on the surface, the situation of the rocks would have been rendered impossible. As Dr. Dawson remarks, wherever the rock is laid bare for the first time, it is found to be thickly covered by these striæ, under the greatest thickness of overlying drift. But were the greater part or all of this drift formed before the depression of the land, and the consequent overflowing of the sea took place, these striæ manifestly could not be formed as asserted. The covering of debris, clay, sand and broken rocks formed by the previous action of the supposed frosts and thaws, would effectually protect the underlying rock from the action of floating ice-bergs and their con

tents.

There is one point connected with this discussion, the satisfactory settlement of which, would exercise a powerful influence, in leading to a conclusion one way or the other. It is asserted positively by those who favour the glacier theory, that there are no marine shells found in the drift proper, and they naturally fix upon this as a strong argument in their favo ur. It is as positively stated on the other hand by Dr. Dawson and those who hold with him, that sea-shells have been found in various localities which are distinctly specified. A question of fact such as this can of course be settled only by additional and more correct observation. In the meantime it may be taken as an approximation to the truth, that if shells of the character stated have been found to occur, it is only at the base or summit of the formation,never throughout the body of it,-and then only in localities not far removed from the sea. The Lower St. Lawrence, the north-east coast of Scotland, and the coasts of Ireland and Wales, are mentioned as places where they have been found, but we have nowhere seen it asserted, that in places far removed from the sea, and towards the centre of the formation they have ever been observed. Another fact which strongly confirms this, is, that five hundred feet is the highest limit above the present sea-level, they have been known to reach.

Should this prove true, the difficulty so far is easily disposed of on the glacier hypothesis. In the early part of the period, when the land first began to rise from the sea, and before the sea had receded from these spots, marine animals lived where their remains are now found. And towards the close of it again when the land had once more sunk to near its previous level, their old home became gradually habitable for them. In the meantime, that is to say, throughout the long period when the main part of the formation was being deposited, these localities with all the region lying to the interior of them, stood above the

level of the sea.

The recent separation of the Boulder drift proper, from the Champlain clays, other superficial deposits makes it probable that mistakes may have occurred in fixing the proper geological horizon of the beds in which the specimens are said to have been found. The presence of shells in the superior deposits is of frequent occurrence, and failure sometimes in distinguishing these from the unstratified clay below may have occasioned the error of assigning to the latter what properly belongs to the others.

Among the chief conditions of the glacier theory, is that of the existence of a temperature so low as to cover the whole surface of the country with a sheet of ice many feet thick, and, secondly, of a slope of, at least, one or two degrees, to allow of the movement of this sheet of ice, in the manner of modern glaciers. The former of these conditions it is believed would be realized, were the land towards the north elevated some five or six thousand feet above its level; and the latter by the unequal surface existing, and the greater accumulation of ice which must have been formed northward. The supporters of the iceberg theory, require for it a subsidence of the land below its present level, of several thousand feet,-a supposition not any more probable than that of an elevation to the same extent. Such a rise, taken in connection with the existence of such high lands as the Laurentides, Adirondacks, Green Mountains, &c., would go far to fulfill all the conditions required. And taken in connexion with the other causes that may have been at work, such as changes in the relative proportions and elevation of land and water, and the varying eccentricity of the earth's orbit, as expounded by Mr. Croll, the difficulties attending the theory in question seem to a large extent to be neutralized by them.

Glaciers are known to move on slopes of not more than one or two degrees; moving ice adapts itself to the inequalities of the surface over which it travels, climbing over hills or passing round them, and sometimes scooping out deep valleys and fiords in the course of their progress, and thus "over the whole surface of a continent" as Mr. Dana remarks," a very little motion would produce in time great results." As regards the formation of fiords it seems impossible satisfactorily to account for them on any other supposition.

The occurrence on the tops of high hills, of boulders which have been transported to a great distance, is fully explained by phenomena with which geologists are familiar, as observed among the Alps. The Pierre-a-bot, a mass of protogine sixty-two feet long by forty-eight feet broad, containing about 40,000 cubic feet, and weighing some 3000 tons, is known to have been transported from Mount Blanc to the Jura mountains over the valleys now occupied by the lake of Geneva, lake Neufchatel, and other Swiss lakes. It lies among immense piles of smaller boulders on the slopes of that part of the Juras which faces the Alps; while the whole region between bears abundant evidence that an immense glacier once moved across it. It was at one time asserted that these boulders must have been transported by means of ice-bergs, but further observation has proved beyond doubt that glaciers were the agents at work.

The occurrence of fossil remains, such as the sea-shells already referred to, and the peat deposits with fir roots, and land snails, mentioned by Dr. Dawson, prove nothing more than that in the earlier part of the boulder period, these organisms lived and died on the spots where their remains are found. They occur as far as has yet been shewn, at the very base of the formation-the shells below the limit of 500 feet above the present sea-level, and must have all become extinct long before the elevation of the continent had reached its highest point. There seems, therefore, to be sufficient ground available, from which

to meet the objections made by Dr. Dawson, to the theory of the origin of the Boulder Drift, by means of the action of glaciers. While, at the same time, the theory which he adopts as sufficient to explain all the phenomena observed, is in many parts of it, surrounded by grave difficulties, and in supporting it he is clearly at variance on several points with the opinion of some whose names he would fain claim in his support. With regard to Sir William Logan for example, while it could not be expected, that in an official report he would formally advocate either side of a question so much disputed as this, there can, we think, judging from the indications given in more than one portion of his work, be little doubt as to which side he inclines. This is specially clear in that part of it in which he treats of the formation of the Canadian lake basins. Dr. Dawson believes them to have been formed, by the action of the waters of the Arctic current, upon rocks of unequal hardness, during the supposed depression of the continent throughout the Boulder period. Sir William Logan, without once referring to this as a probable cause, says ;-"These great lake-basins are depressions not of geological structure but of denudation; and the grooves on the surfaces of the rocks which descend under their waters, appear to point to glacial action as one of the great causes which have produced these depressions." And in a note to this passage, after giving Professor Ramsay's opinion as to a similar origin of the lake-basins of Europe, he goes on to state that the facts enumerated in the text, "go far to show that the fresh water basins of North America have had a similar origin. This hypothesis points to a glacial period," he continues "when the whole region was elevated far above its present level, and when the Laurentides, the Adirondacks and the Green Mountains, were lofty. Alpine ranges covered with perpetual snow, from which great frozen rivers or glaciers extended far over the plains below, producing by their movements the glacial drift, and scooping out the rivervalleys, and the basins of the lakes. Dr. J. S Newbury has pointed out in a very clear manner the evidence of this former extensive glacial action in North America." After this, it might be thought, one would rather hesitate to state that Sir William Logan with his usual caution, has not committed himself to the glacier theory.

It is especially worthy of notice, that Dr. Dawson, in common with nearly all who have written on the subject, whichsoever of the above theories they may have adopted, meets once and again with appearances which his favourite theory will not explain, and feels constrained to call in the assistance of that which he combats. For instance in speaking of striæ observed in some portions of New England, he says: "Nor would I exclude altogether the action of glaciers in Eastern America, though I must dissent from any view which would assign to them the principal agency in our glacial phenomena." And further on he remarks in a note "I have no doubt that Logan, Hind and Packard are correct in assigning some of the striation in the Laurentide Hills of Canada and Labrador to glaciers. The valley of the Saguenay, which is a deep cut caused by denudation along a line of fracture traversing the Laurentian rocks, shows near its mouth distinct "roches moutonnees," smoothed on the northern side, and very

deep grooves and striæ cut in hard gneiss with a direction of S. 10 E. magnetic, which is nearly at right angles to the ordinary striation of the St. Lawrence valley. I think it quite possible that these appearances may have been caused by a local glacier, and if so, there may have been glaciers along the whole line of the Laurentide Hills, with their extremities reaching to the sea or strait then filling the St. Lawrence valley."

On the other hand, Dana, who holds strongly to the glacier theory, in his "Manual of Geology," makes a similar admission in favour of that which assigns the production of certain effects to ice-bergs. "In view of the whole subject," he remarks in his chapter on the 'PostTertiary Period,' "it appears reasonable to conclude that the glacier theory affords the best and fullest explanation of the phenomena over the general surface of the continents, and encounters the fewest difficulties. But ice-bergs have aided beyond doubt in producing the results along the borders of the continents, across ocean channels like the German ocean and the Baltic, and probably over great lakes like those of North America. Long Island Sound is so narrow that a glacier may have stretched across it. In Europe ice-bergs were evidently more extensive in their operation than in America. Glaciers have probably continued there in action from the time of their first appearance on the continent to the present day; and the glacial era on that continent may not, therefore, be the well-defined period that it is in North America."

Like the dispute that raged so long and so fiercely between rival schools as to the igneous or aqueous origin of rocks, this, as to the origin of the boulder drift, may end by a mutual compromise between the two theories now so keenly advocated. There are facts which cannot be explained by either exclusively, while both combined with the necessary limitations, seem amply sufficient for the explanation of all. Many of Dr. Dawson's positions in support of his favourite hypothesis seem all but impregnable on the facts to which they appeal; but as has been shown above, his objections to the theory he combats are by no meaus unassailable. It would have been preferable, however, if the discussion must be admitted within his pages, had he furnished us with a more full and candid statement of the arguments on the other side. This in so limited a space it would be perhaps inconvenient to give, and it were better to have omitted the discussion altogether, and confined his attention to the facts and phenomena he may have observed in connection with the formation.

CHARLES SANGSTER, AND HIS POETRY.*

On the 16th of July, 1822, at Kingston, Ontario, was born Charles Sangster. His grand father was an U. E, Loyalist who attained some notoriety in the American Revolutionary War, as an attache of the Royal Army, and his father, who died when young Charles had

*The "St. Lawrence and the Saguenay, and other poems." by CHARLES SANGSTER, Kingston, Ontario, John Creighton and John Duff, New York, Miller, Orton & Mulligan. "Hesperus and other poems," by CHARLES SANGSTER, Montreal, John Lovell, Kingston, John Creighton.