250 SUBTERRANEAN VILLAGES NEAR TRIPOLI. 



From the entrance of Gonzalo da Cintra, on the coast of 

 Barbary, to Cape Verde, all the elevated points of solid 

 rock are said to be of igneous origin : thus Cape Barbas, 

 Cape Blanco, Cape Manuel, and Cape Verde are composed 

 of basalt and lava. All the islands, too, along this west 

 coast we of igneous origin. 



In this vast waste there are a few oases and wadeys, or 

 valleys, in which springs of water are found, and shrubby 

 plants, chiefly acacias, and tufts of grass. It is inhabited 

 only by pastoral tribes, who roam about from one oar^is to 

 another, where a little verdure may be found. Some of 

 these tribes add to their scanty means of subsistence the 

 plunder of such feeble caravans as they may venture to 

 attack; and others are employed in collecting salt and natron 

 for the markets of Bornou and Soudan. For hundreds of 

 miles not an oasis is seen, the surface being one continued 

 plain ; in some places blown up into high ridges, in others 

 presenting undulations like the waves of the sea. In parts 

 of the Desert, insulated hills, or ridges of hills of naked sand- 

 stone, sometimes also of granite, rise through the sandy 

 surface, appearing like so many islands in the ocean. 



Account of the Line of Desert from Tripoli to the Lake 

 Tchad. — The line of desert, extending from Tripoli by 

 Mourzouk to Kouka, has been described by our former 

 pupil the late excellent and intelligent traveller Dr. Oudney, 

 and by his enterprising fellow-travellers Clapperton and 

 Denham. As the account is novel and interesting, we shall 

 now lay some details illustrative of it before our readers ; 

 occasionally, also, referring to the observations of another 

 well-known African traveller, Captain Lyon.* 



Subterranean Villages. — All around Tripoli the prevail- 

 ing rocks are of limestone, — partly of secondary, partly, it 

 is said, of tertiary formation. The Arab inhabitants of the 

 Gharian limestone mountains in Tripoli live under ground^ 

 -—a circumstance worthy of being particularly recorded, on 

 account of its connexion with the ancient history of man, 



* To those interested in African adventure, we recommend an in- 

 teresting little volume just puhlishfd, entitled, " A Biographical Memoir 

 of the late Dr. Walter Oudney and Captiiin Hugh Clapperton, both of tho 

 royal navy, and Major Alexander Gordon Laing, all of whom died afiiid 

 their active and enterprising endeavours to explore the interior of Africa. 

 By the Rev. Thomas Nelson, Member of the Wemerian Society, &c • 

 l2mo. Edmburgh, 1«30, by Waugh and Innea. 



