This collection of primary sources examines scientific methodology in Britain during the long nineteenth century. Over the course of the nineteenth century, emblematically but not exclusively represented by the work of Charles Darwin, natural science reconfigured the ways in which practitioners would treat the sciences of "deep time" – especially geology and the new theory of natural selection. This volume uses primary sources and editorial commentary to examine the topics of geology and evolution in this period. This title will be of great interest to students of the history of philosophy and the history of science.