by Surgeon O'Beirne and Major Laing.
Relief shown by hachures.
"Compiled from original documents in the Colonial Office."
Includes text, "The Route from Kowia to the Source of the Niger," "Explanation of the Routes: Wall and Winterbottom in 1794, Orange, Surgeon O'Beirne's Route in 1821, Green, Major Laing's Route in 1822, Red, Jack Bore's Route described by Major Laing 1822, Yellow," "Major Laing's Table of Lat & Long.
Includes table of longitude and latitude and table of "Returns of the trade population &c of Sierra Leone 1817 to 1825."