Note 51 — Chapter II

Indeed it goes beyond it: ‘the trackless sands of the Sahara desert, which is even prolonged for miles into the Atlantic Ocean in the form of sandbanks.’ Somerville's Physical Geography, vol. i. p. 149. For a singular instance of one of these sandbanks being formed into an island, see Journal of Geograph. Society, vol. ii. p. 284. The Sahara desert, exclusive of Bornou and Darfour, covers an area of 194,000 square leagues; that is, nearly three times the size of France, or twice the size of the Mediterranean. Compare Lyell's Geology, p. 694, with Somerville's Connexion of the Sciences, p. 294. As to the probable southern limits of the plateau of the Sahara, see Richardson's Mission to Central Africa, 1853, vol. ii. pp. 146, 156; and as to the part of it adjoining the Mandingo country, see Mungo Park's Travels, vol. i. pp. 237, 238. Respecting the country south of Mandara, some scanty information was collected by Denham in the neighbourhood of Lake Tchad. Denham's Northern and Central Africa, pp. 121, 122, 144–146.