G. K. GILBERT, EVERETT HAYDEN, WILLARD D. JOHNSON, _Committee on Exploration_. NOTES. _La Carte de France, dite de l'Etat Major, par M. J. Collet. Paris, 1887. 8vo, pp. 92, with 4 plates._--This pamphlet describes the great "Staff Map" of France, recently completed, giving its history, the methods employed in the field and office work, the contents of the map, and the means of representing the various features therein described. The scale of the map is 1:80,000. Relief is represented by hachures, for drawing which approximate contour lines have been located, but these are not otherwise used. A great variety of cultural features are shown, many of which are ephemeral, and which contribute to the overloading of the map with details. Moreover, as the time which has ordinarily elapsed between the survey and the issuance of the work in printed form is ten or twelve years, most of this culture has become not only of no value but misleading by the time it is published. The account of the organization and methods by which the map has been produced is of special interest. The primary triangulation upon which it is based is one of the most elaborate and accurate ever executed in any country. No expense has been spared in this direction. Within this triangulation is a secondary triangulation, also very elaborate, from the stations of which numerous additional points are cut in, or located by unclosed triangles. All this work is of the highest order of excellence, being infinitely more accurate than the map requires. {251} With this, however, the accuracy appears to end. The detail consists of the map, or the map proper, little more than a compilation of commune cadastral plans. These were fitted to the triangulation points and to one another, a process which appears to have been by no means easy of satisfactory accomplishment. This adjustment having been completed, the culture was brought up to date of survey and a survey was made of the relief features by the use of such inferior instruments as the clinometer compass and chain. The principal and obvious criticism upon such work is that it is top-heavy. The triangulation is far more elaborate than is required, while the provision for making the map itself is by no means comparable with it: it is as far below the requirements of the scale as the triangulation is above it.