It thus appears that the whole range of the Grampians formed a great centre for the distribution of glaciers, and that a colossal ice-field spread itself over the whole country, extending in every direction toward the lower lands and the sea-shore. As the glaciers which now descend through all the valleys of the Alps, along their northern as well as their southern slopes, and in their eastern as well as their western prolongation, though limited, in our days, within the valley-walls, nevertheless once covered the plain of Switzerland and that of Northern Italy, so did the ice-fields of the Grampians during the greatest extension of the Scotch glaciers spread over the whole country. They also were, in course of time, reduced to local glaciers, circumscribed within the higher valleys of the more mountainous parts of the country, until they totally disappeared, as those of Switzerland would also have done, had it not been for the greater elevation of that country above the level of the sea. Scotland nowhere rises above the present level of perpetual snow, while in Switzerland the whole Alpine range has an altitude favorable to the preservation of glaciers. In the range of the Jura, however, which had at one time its local glaciers also, but which nowhere now rises above the line of perpetual snow, they have disappeared as completely as in the Grampian Hills. It would lead me too far, were I to give here a special account of all the investigations I made in 1840 upon the distribution of glaciers in Great Britain. I will therefore only point out a few of the more distinct areas of distribution. The region surrounding Ben Wyvis formed such a centre of dispersion from which glaciers radiated, and we have another in the Pentland Hills about Edinburgh. In Northumberland, the Cheviot Hills present a glacial centre of the same kind, and in the Westmoreland Hills we have still another. In the last-named locality, the glacial tracks can be followed in various directions, some of them descending toward the northwest from the heights of Helvellyn, others moving southward toward Ambleside. In Wales the same kind of glacial distribution has been observed; but, as Professor Ramsay has treated this subject in full, I would refer my readers to his masterly work for a further account of the ancient Welch glaciers. In Ireland I had also opportunities of making extensive local investigations of glacial action. I observed the centres of distribution in the neighborhood of Belfast, in the County of Wicklow, and in Cavan.