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its physical characters that the Lafayette formation has been investigated and largely explained.

The author of "The Lafayette Formation" has made one of the most important recent contributions to geological science. Besides his contribution to the geology of an enormous area, the principles of geomorphy are emphasized, and the interpretation of the continental changes of the later Tertiary days are set forth in an original manner, forming one of the most interesting chapters in dynamical geology.

The maps are particularly worthy of attention. The first represents the physiography of the coastal plain, and its relations both with the higher land area and deeper oceanic depression. The next is a colored map showing the distribution of the Lafayette formation and the overlying Columbia. The third map shows the continental area during the Lafayette subsidence; it is both a topographical and hydrographical chart of the physical features of land and sea when 250,000 square miles of the southeastern part of the continent was submerged. It is of special interest. Then follows the topographical map of the high continent during the post-Lafayette elevation, when the continental region was expanded by 100,000 miles or more in excess of that of modern times. The last map shows the continental contraction during the Columbia period—and a very strange looking map it is with the land margin dissected by numerous estuaries, scores of hundreds of miles in length, resulting from the submergence of the great valleys of the south in connection with the tilting of the land toward the South Carolina axis of oscillation.

Although this work was commenced by others, yet the extension and digestion of the whole belongs to the author, and it is a remarkably meritorious work. But in the study of geomorphy, and of the most interesting continental changes, the work is almost entirely original. The whole forms one of the most complete, yet peculiar, chapters of American geology. This review is only sufficient to call attention to a very suggestive report in which, however, there are still some questions left open. The author is to be congratulated on having taken up such an important and interesting but little known subject, and for working it out to such a degree of completion.