Ch. XXIX.] FOSSIL PLANTS OF MADEIKA. 649 



ward course, they flowed with a steep inclination, often at an angle of 

 17 degrees, towards the south. Nearer the sea, as at i and L, on both 

 sides of the island, where the most modern lavas occur, the dip dimin- 

 ishes to 5 degrees, and even to 3^-, as at k, near Funchal. In this 

 latter characteristic (the smaller inclination of the lavas near the sea, 

 and their association there with modern cones of eruption, such as m, 

 x, o) there is a strict analogy between Madeira and Palma. Distinct 

 buried cones of eruption also occur at many points, as at p and q, fig. 

 706, which have been overwhelmed by lavas flowing from the central 

 region. 



As a general rule, the lavas of Madeira, whether vesicular or com- 

 pact, do not constitute continuous sheets parallel to each other. 

 AYhen viewed in the sea-cliffs in sections transverse to the direction in 

 which they flowed, they vary greatly in thickness, even if followed for 

 a few hundred feet or yards, and they usually thin out entirely in less 

 than a quarter of a mile. In the ravines which radiate from the centre 

 of the island, the beds are more persistent, but even here they usually 

 are seen to terminate, if followed for a few miles ; their thickness also 

 being very variable, and sometimes increasing suddenly from a few 

 feet to many yards. 



We saw no remains of fossil plants in any of the red partings or 

 laterites above alluded to ; but Mr. Smith, of J ordanhill, was more 

 fortunate in 1840, having met with the carbonized branches and roots 

 of shrubs in some red clays under basalt near Funchal. Nevertheless, M, 

 Hartung and I obtained satisfactory evidence in the northern part of the 

 island, in the ravine of S. Jorge, of the former existence of terrestrial 

 vegetation, and consequently of the subaerial origin of a large portion of 

 the lavas of Madeira. At q in the section (fig. 706) the occurrence of a 

 bed of impure lignite, covered by basalt, had long been known. Asso- 

 ciated with it we obserred several layers of tuff and clay or hardened 

 mud, m one of which leaves of dicotyledonous plants and of ferns abound. 

 Sir Charles J. F. Bunbury, who was with me in Madeira during the 

 winter of 1853-4, at once pronounced one of the fossil ferns to ao-ree 

 in its peculiar vernation with Woodivardia radiccms, a species now 

 common in Madeira; and he afterwards discovered the common Ma- 

 deira fern, Davallia Canariensis, and a Nephrodium, and other ferns 

 among the fossil remains. He also pointed out that, among the dico- 

 tyledonous leaves, some were of the mptle family, the larger propor 

 tion having their surfaces smooth and unwrinkled, with a somewhat 

 rigid and coriaceous texture, and with undivided or entire margins. 

 " These characters," observed Sir C. Bunbury, " belong to the laurel- 

 type, and indicate a certain analogy between the ancient vegetable re- 

 mains and the modern forests of Madeira, in which laurels and other 

 evergreens abound, with glossy coriaceous and entire-edged leaves, 

 while below them there is an undergrowth of ferns and various other 

 plants." * 



* Bunbury, Quart. Geol. Journ., 1854, vol. x. p. 326. 



