Charles Darwin’s final transect aboard HMS Beagle: Cape Town to Shrewsbury May-October 1836

There is some evidence that Charles Darwin was somewhat tired and homesick on the last leg of the Beagle’s voyage, from Cape Town to Falmouth, May to October 1836. However, his geological observations remained at a high level, and numerous rock specimens were collected in Cape Province, at Bahia and Pernambuco in Brazil, and on the volcanic islands of St. Helena, Ascension, St. Jago (Cape Verde Islands), and Terceira in the Azores. Throughout the voyage, he frequently adopted a comparative approach. Thus, he noted similarities amongst the granite landscapes of South Africa, Australia (seen earlier in the voyage), and South America, both from his fieldwork and his reading of Humboldt’s Personal Narrative. He also saw similarities (and differences) among the volcanic islands in topography, petrology, and mineralogy. By this stage, steeped in the doctrine of uniformitarianism from his reading of Lyell’s Principles of Geology, he understood that processes of both land formation and denudation had been at work throughout long periods of geological time. Frequently, Principles and Narrative must have been open alongside his notes as HMS Beagle sailed homewards. Thus did Charles Darwin embrace the conceptual framework of gradualism, which later of such importance.