The growth of a prehistoric timescale was one of the most dramatic developments in nineteenth-century ideas of humanity, massively extending the assumed course of human development and placing it within the deep chronologies of geological time. A dominant motif linking anthropology and prehistory was the 'comparative method' -the idea that modern 'savages' were analogous to prehistoric Europeans, most dramatically proposed in the many editions of John Lubbock's Pre-Historic Times, but also found across a host of other works. The importance of this mode of reasoning has been well-studied, and shown to have had great significance for concepts of progress and social evolution. What has been less investigated is what happened when the comparative method broke down, and 'modern savages' and 'prehistoric man' seemed to be dissimilar, and the analogies either broke down, or were hard to reconcile. This paper examines how a series of authors engaged with these problems as they attempted to historicize human development in the deep prehistoric past. In doing so, it will highlight what was seen as unique about European prehistory, and the development of anthropological methods and concepts.2/31