1. Africa with the discoveries to May 1858 of Livingstone, Barth, Vogel, & of the Chadda expedition, from documents in possession of the Royal Geographical Society (Raster Image) Datasets Stanford University Public content 1858. Swanston, George H. and Stanford Geospatial Center. This layer is a georeferenced raster image of an historic continental map of Africa created in 1860. Originally created by George Swanton, this map... Stanford Digital Repository.