The Committee on Stratigraphy of the National Research Council introduces herewith a series of 12 charts showing the classification and correlation of the post-Proterozoic sedimentary formations of North America. These charts have been under study and preparation for nearly 10 years and represent the combined efforts of a large group of American stratigraphers.
Since some of the charts are now completed, whereas others will require further preparation, the plan is to publish them individually as they are ready and without regard to stratigraphic order. Each chart, with several pages of annotations, will form an individual paper in the Bulletin. The first of them follows in this issue. It is planned to publish a considerable number of reprints which may be purchased separately or in sets.
The complete set will include the following:
Chart No. 1. Cambrian Formations of North America, by B. F. Howell, et al.
Chart No. 2. . . .