If I am asked whether the "Principles" or the "Manual" should be studied first, I feel much the same difficulty in answering the question as if a student should inquire whether he ought to take up first a treatise on Chemistry, or one on Natural Philosophy, subjects sufficiently distinct, yet inseparably connected. On the whole, while I have endeavored to make each of the two treatises, in their present form, quite independent of the other, I would recommend the reader to study first the modern changes of the earth and its inhabitants as they are discussed in the present volume, proceeding afterwards to the classification and interpretation of the monuments of more remote ages.
Charles Lyell.
11 Harley Street, London, May 24, 1853.
Dates of the successive Editions of the "Principles" and "Elements" (or Manual) of Geology, by the Author.
| Principles, 1st vol. in octvo, published in | Jan. 1830. |
| —————, 2d vol. in octvo, published in | Jan. 1832. |
| —————, 1st vol. 2d edition in octavo | 1832. |
| —————, 2d vol. 2d edition in octavo | Jan. 1833. |
| ————— 3d vol. 1st edition in octavo | May, 1833. |
| —————, New edition (called the 3d) of the whole work in 4 vols. 12mo | May, 1834. |
| —————, 4th edition, 4 vols. 12mo | June, 1835. |
| —————, 5th edition, 4 vols. 12mo | Mar. 1837. |
| Elements, 1st edition in one vol | July, 1838. |
| Principles, 6th edition, 3 vols. 12mo | June, 1840. |
| Elements, 2d edition in 2 vols. 12mo | July, 1841. |
| Principles, 7th edition in one vol. 8vo | Feb. 1847. |
| —————, 8th edition in one vol. 8vo | May, 1850. |
| Manual of Elementary Geology (or "Elements," 3d edition) in one vol. 8vo. | Jan. 1851. |
| Manual, 4th edition, one vol. 8vo | Jan. 1852. |
| Principles, 9th edition, now published in one vol. 8vo | June, 1853. |