The regular book publications of the Geological Survey are issued in three sizes—(1) octavo (annual reports of the Director, statistical reports on mineral resources, bulletins, and water-supply papers); (2) quarto (professional papers and monographs); (3) folio (geologic folios). The following table gives the measure of the text of each size and the measure of the trimmed page, in inches:
| Size of text. | Size of page. | ||||||||||
| Octavo | 4 | 3/8 | by | 7 | 15/16 | 5 | 7/8 | by | 9 | 1/8 | |
| Quarto | 6 | 1/16 | by | 9 | 1/8 | 9 | 1/4 | by | 11 | 5/8 | |
| Folio | 13 | 13/16 | by | 17 | 7/8 | 18 | 1/2 | by | 21 | 3/4 | |
Most professional papers are printed in two columns of type, each 3 inches wide, and folios are printed in three columns, each 43/8 inches wide. A text figure in one of these publications can be made to fit one or more columns, and it may run the full length of the text page.
The limits of the dimensions of plates and figures, in inches, are given in the following table. If for any reason a plate can not be reduced to the dimensions of a page it can be folded once or more; and if it is large and unwieldy it may be placed in a pocket on the inside of the back cover. (See [Pl. I].)
| Single-page plate. | Plate with one side fold. | Text figure. | |||||||||||||
| Octavo | 4 | 3/8 | by | 7 | 1/2 | 7 | 1/2 | by | 8 | 1/2 | 4 3/8 | by | 7 | 1/2 | |
| Quarto | 6 | by | 9 | 9 | 1/2 | by | 14 | 3/4 | 3 or 6 | by | 8 | 1/2 | |||
| Folio | 15 | by | 17 | 1/2 | ............ | 43/8 or 1313/16 | by | 17 | 7/8 | ||||||
For an octavo report a single-page plate with side title should be 4 inches or less in width, and a plate with bottom title should be 7 inches or less in depth. In other words, the actual depth and width of a single-page plate in a page of any size must depend on the number of lines in its title, the inclusion of which should not extend the matter much, if any, beyond the dimensions given in the table. A difference of 1 inch or less in the width of a folding plate may determine whether it must be folded once or twice, so that by consulting this table an author may save expense in binding and promote the reader's convenience in handling the plate.
A text figure (including the title) can not extend beyond the text measure but may be of any size or shape within that measure, as shown on [Plate I], figures 4, 8, 9, 10.
SUBDIVISIONS OF PLATES AND FIGURES.
If a plate consists of two or more parts or photographs each part should be marked with an italic capital letter—A, B, etc.—which should be placed directly under each. If it is made up of many parts, in the form of plates that accompany reports on paleontology, each part should be similarly marked with an arable numeral—1, 2, 3, etc. If a text figure is subdivided into two or more parts, each part should be marked with a roman capital—A, B, C, etc.; and if details of a part are to be described each detail should be marked by an italic lower-case letter—a, 6, c, etc.