HARTUNG — CANARY ISLES. 13 



The Geology of Lanzarote and Fuertaventura. By George 

 Hartung. 4to, pp. 164; 1 Map and 1 1 Plates. [1857.] 



Die geologischeVerh'dltnisse derlnseln Lanzarote und Fuertaventura 

 von Georg Hartung. [No place or date.] 



Mr. Hartung is a German naturalist, who, having studied under Sir 

 Charles Lyell the volcanic phenomena of Madeira, Teneriffe, Grand 

 Canary, and Palma *, subsequently went alone to Fuertaventura and 

 Lanzarote, two other islands of the Canary group. He carefully ex- 

 amined these little-known islands, and now gives us an account of 

 them in the interesting memoir before us, which may be pronounced 

 a valuable contribution to science, and one that shows he is a pupil 

 of whom his master may be proud. 



The memoir is illustrated by a large map of the islands, two large 

 panoramic views, and nine plates of sections, &c. It is divided into 

 three parts : in the first, the author presents us with a personal 

 narrative of his wanderings and a sketch of the fauna and flora (in 

 the latter he discovered some plants hitherto undescribed) ; in the 

 second, he gives a sketch of the physical geography; and in the third, 

 he describes the geological phenomena. 



The islands in question are the most easterly of the Canary group. 

 They lie end to end, Lanzarote being the nearest to the African coast, 

 from which it is distant only twenty-eight geographical miles. Fuer- 

 taventura has a length of about thirty-two geographical miles, and a 

 superficies of about four hundred and eighty square-miles. Lanzarote 

 has a length of about twenty-one geographical miles, and a superficies 

 of about two hundred and ten square-miles. The two are separated by 

 a channel some six or eight miles wide, in which lies a small island 

 called Lobos (Seal's Island) ; and at the eastern extremity of Lanzarote 

 are three islets bearing the flattering titles of Graciosa, Clara, and 

 Allegranza, names strongly contrasting with the barren realities. The 

 shape of Lanzarote is rather like that of an ill-formed S, that of its 

 neighbour is tolerably straight, and its western extremity terminates 

 in a long narrow promontory containing a lofty ridge, and separated 

 from the main island by a low neck covered with white calcareous 

 sand. The islands are altogether volcanic, and are studded with a 

 great number of cones, the highest of which in Fuertaventura reaches 

 the altitude of 2770 feet, in Lanzarote of 2240 feet. Both are ex- 

 tremely barren, having few springs of water (in Lanzarote there is 

 only one spring of fresh water), and being exposed in summer to 

 great heat. 



Looking at the geological structure of these islands with reference 

 to age, Mr. Hartung tells us that four formations may be distin- 

 guished, viz. — 



1 . The syenitic greenstone and trap formation ; and 2, 3, and 

 4, the oldest, middle, and newest basalt formations. 



1 . The first consists of syenitic greenstone, trachyte, and basaltic 

 greenstone, without any intermixture of scoriaceous matter. The 



* See Lyell's ' Manual of Geology,' 5th edit. p. 498, &c. 



