Page:Popular Science Monthly Volume 37.djvu/285

Rh or other special character of the exposure may prove inapplicable to the representative of the same group in some other situation. The systems, as they are known in North America, are then described in their order, beginning with the Laurentian, in the first ninety pages; and the typical localities and general extent of each are noticed. The rest of the volume is occupied with the paleontological manual; and this is introduced with an ample exposition of the rules of nomenclature. The list is classified, beginning with the plants, and passing through the animal orders to the batrachians, each sub-kingdom and class being introduced by a text describing its characteristics and its orders. The names of all the species, arranged in alphabetical order, are given under the genera to which they belong, with the authors of them, the dates of publication, and, frequently, references to two places of publication. The cases are marked when generic and specific names are not known to occur in the Palæozoic rocks of North America; of synonyms, names not described as required by the rules of nomenclature, preoccupied names, and names condemned for any other reason; and erroneous references of species to genera are pointed out and corrected. A large proportion of the genera are illustrated by engravings of typical species.

is a very extensive and important "mound-builders'" earthwork, overlooking the Little Miami River and its failroad, a few miles above Cincinnati. It is described by the author as "the greatest of all prehistoric earthworks in the Mississippi basin." Mr. Moorehead conceived that a full account of so remarkable a structure was desirable, and prepared himself conscientiously to furnish it. The first step was to make a survey, and for this, with a corps of competent workers, he went over the entire structure many times, and carried on a work which, he trusts, will need no additional researches to complete. In this he was assisted by Mr. Gerard Fowke and Mr. Clinton Cowen. The main purposes of the writer have been to set before the public, in as brief and exact a manner as possible, the prominent features and wonders of the monument, and to insist upon its purchase and preservation by some historical or scientific association. The fort is situated upon a plateau standing close to the river-bank, at a height of 269 feet above low water, and about 900 feet above the level of the sea. The irregular contour of the work is 18,712 feet in length, but a diameter drawn from north to south is only 4,993 feet long. The structure consists of two large incisures, called the old and new forts, connected by a narrower passage-way which the author calls the isthmus. At the southern end of the isthmus, where it is narrowest, is the "great gateway," guarded by a mound on either side. Opposite it, at about one third of the length of the isthmus, is the "Crescent Gateway." The space between these gateways is called the "Middle Fort," and appears to have been the strongest part of the work. Numerous graves, skeletons, and remains of human work were found in and around the fortifications, and evidences of an ancient village site in the valley. The whole proves to the mind of the author that Fort Ancient was built for defense; that it was a rallying-point for a large population inhabiting a district of considerable extent, and was often the scene or the witness of fierce battles. It may have been used as a fortified village site, with people living within its walls all the time—not enough to command the inclosure, but enough to keep it in good repair. A high opinion is expressed of the ability of the constructors. They showed extraordinary patience, and "have left evidence of the possession of qualities seldom found among savages. They engineered the position of the walls with reference to the most secure places with admirable skill." With no tools, such as we use, and wicker baskets and skins as the only means of conveyance, by mere strength of hand and back, they accomplished a work before which we, even with our modern implements, would hesitate. The selection of the site, "the best for the purpose which the valley of the Ohio offers"; the skill with which the walls were carried around the entire inclosure; the care with which weak and exposed points have been