What was the title of Darwin's 1846 book on the geology of South America?

Darwin’s 1846 book on the geology of South America was titled Geological Observations on South America.

The book was based largely on observations Darwin made during the second voyage of HMS Beagle, commanded by Robert FitzRoy from 1831 to 1836. During the expedition, Darwin examined coastlines, fossils, rock formations, and mountain landscapes across areas corresponding to modern Brazil, Argentina, Chile, and other parts of South America.

Published in 1846, it was the third volume in Darwin’s geological series about the Beagle voyage. It followed The Structure and Distribution of Coral Reefs, published in 1842, and Geological Observations on the Volcanic Islands visited during the Voyage of H.M.S. Beagle, published in 1844.

The work discussed the geology of the Andes, Patagonia, the Pampas, and other regions, including evidence for the gradual uplift of the South American continent. It also examined fossils and strata to estimate the relative ages of rocks. A frequent quiz mistake is to choose Journal of Researches, Darwin’s broader travel narrative, or one of his other geological books rather than this specifically South American volume.