Page:A Treatise on Geology, volume 1.djvu/10

iv more accurate expression, as a problem, by some laws of phenomena which my own observations, and those of Mr. Sharpe, have added to the well known determinations of Sedgwick; and Mr. Hopkins, ever ready to give a mathematical form to geological truth, has shown how mechanical theory desires to look at this problem. (Vol. II. p. 111, et seq.)

The dispersion of detritus from the mountains of Scandinavia, Britain, and the Alps has undergone critical re-examination, with reference to the change of level of the land, action of great waves of translation, variation of climate, extension of glaciers, and transport of icebergs. The separate labours of Murchison, Hopkins, Agassiz, J. Forbes, Darwin, and others, have thrown on this complicated subject new, varied, and effective illumination. (Vol. II. p. 11, et seq.)

I must not be prevented by the share which I have had in the Memoirs of the Geological Survey of Great Britain, from referring to this publication, and the Maps which it illustrates, for some valuable additions which have been made to British and Irish geology. Under the guidance of De la Beche, Mr. Ramsay and my other friends have cleared away from Wales whatever obscurity remained, after the strong light thrown on it for so many years by Sedgwick. Professor E. Forbes, now in charge of the Palæontological department of this Survey, has brought to the philosophical study of its rich collections matured views on the distribution of marine life views founded on assiduous dredging round the British shores, and an admirable survey of the depths of the Ægean. (Vol. I. p. 326─335.)