'Sketch Map of Sikhim and of the Nepalese Frontier' ‘This map is based on the trigonometrical surveys of Lieutenant Colonel Waugh, from the positions and altitudes of the principal peaks are laid down. The details are derived from Dr [William] Hooker’s observations as given in his sketches and papers, partly in Major Crommelin’s Map’. The map includes Dr Hooker’s route depicted in a dotted line. c.1850