SUMMARY R. E. Grant's advocacy of transmutation is considered in relation to the scientific climate of the 1850s. To understand the palaeontological framework of his development theory, the unpublished “Palaeozoology” lectures, delivered in 1853–7, are analysed and his sources tabulated. The lectures are shown to contain the following additional themes: (1) a refutation of Lyell's steady-state geology, (2) support for serial development, (3) use of metamorphic effacement to explain the lack of pre-Silurian fossils, and (4) nebular hypothesis. The difficulty of supporting serial development using fossil evidence at this late date is discussed, and this difficulty is deemed to have contributed to the failure of Grant's theory of species “generation”.
