THE Report of the Geological Survey of the Transvaal Mines Department for 1904 (Pretoria, 1905, price 7s. 6d.) is a folio volume, issued at a very moderate price. It contains twenty-three plates, from which our figures are reductions, and two large coloured maps, the latter being conveniently placed in an envelope at the end. The cessation of topographical work in the country must in future hamper systematic geological mapping, and the Geological Society of South Africa has already approached the Colonial Secretary in Pretoria on the subject (Proc. Geol. Soc., S. Africa, 1906, p. liv). It might be thought that military considerations alone would be sufficient to place an accurate map among the first requirements of the colony.