A Geognostical Essay on the Superposition of Rocks in Both Hemispheres

The explorer and multi-disciplinary scientist Alexander von Humboldt (1769–1859) was a prominent figure in the European scientific community of the eighteenth and nineteenth centuries and the first to make a scientific survey of South and Central America. His travels alone brought him widespread recognition, but the extensive field notes and research he undertook were developed further on his return. Originally published in French and translated in 1823, this work brought his geological speculations to a British audience. Humboldt explores the positioning of different types of rocks across the globe, and the causes behind these formations. He also hypothesises that the flora of these areas are affected by the geology, which in turn is influenced by the thermal currents of the earth's molten core. These insights into rock formations are also key to Humboldt's theory of continental drift, now recognised as resulting from the shifting of the continental plates.