Geological Observations on South America is a book written by the English naturalist Charles Darwin. The book was published in 1846, and is based on his travels during the second voyage of HMS Beagle, commanded by captain Robert FitzRoy. The HMS Beagle arrived in South America to map out the coastlines and islands of the region for the British Navy. On the journey, Darwin collected fossils and plants, and recorded the continent's geological features.