Geological Sketches. By L. Agassiz. (Trabner.) — The articles collected
in this volume, first delivered as lectures, then published in the Atlantic Monthly, are to be considered, in the words of the author, rather as familiar talks on scientific subjects than as scientific papers. They -will be all the more welcome to a good many rea dere, for they are divested of the dryness, whilst they retain the accuracy, of science. The author has enjoyed the -immense advantage of studying his subject in the New World as well as the Old, and is at home both in the Alps and in those interesting Laurentian hills, stretching from Eastern Canada to the Upper Mississippi, that first broke the uniform level of the earth's surface, and lifted themselves above the primeval waters. His style is attractive, and there is just that touch of Continental liveliness which is very pleasant, duly restrained as it is by scientific training. The lectures embrace the successive geological eras, from the upraising of the Silurian beach in North America, that constituted the first land, thereby entitling that oontinent to the designation of the Old World, to- the glacial period ; and any one who reads them carefully will find himself possessed in an agreeable way of the leading facts of the science. The author concludes with a couple of lectures on the internal structure and progression of glaciers, and announces his intention of treating this. subject at greater length in a fixture volume. Owing to the extensive. laud, surfaces on the American continent, the same set of facts presents. quitea different aspect there and in the Old World, and M. Agassiz. hopes to be enabled to throw some new light on the verata quastio of glacial phenomena.