The previously unpublished correspondence of T.H.Huxley with Rev. George Gordon is an important new addition to the literature on Huxley and Victorian science. The correspondence is self-contained and wholely scientific, concerning the unexpected discovery of reptilian fossils and footprints near Elgin, and relates to a most important aspect of Huxley's career: defining the relationship between geology and palaentology. The letters are complemented by an incisive analysis of Huxley's work as a palaentologist and the development of his views on evolution.