APA (7th ed.) Citation

Lyell, C. (2010). Principles of Geology or, The Modern Changes of the Earth and its Inhabitants Considered as Illustrative of Geology. Project Gutenberg.

Chicago Style (17th ed.) Citation

Lyell, Charles. Principles of Geology or, The Modern Changes of the Earth and Its Inhabitants Considered as Illustrative of Geology. Project Gutenberg, 2010.

MLA (9th ed.) Citation

Lyell, Charles. Principles of Geology or, The Modern Changes of the Earth and Its Inhabitants Considered as Illustrative of Geology. Project Gutenberg, 2010.

Warning: These citations may not always be 100% accurate.