AND PORTO SANTO. 68 



conceived from the drawing, Plate 6, which gives the different 

 appearances and colours of the tufa, of the dark scoriaceous matter 

 between, of the imbricated-looking basalt beneath, and of the 

 principal dike, which is three feet four inches wide ; the smaller 

 sketch, Plate 3, D, taken from a higher point, and at a greater 

 distance, should be referred to at the same time. To the left of 

 the part represented in the larger drawing, the dikes descend 

 through red tufa, which reposes on scorife. The descent to the 

 beach is rather difficult, and I slid the greater part of the way 

 over a black cinder, the basaltic masses above which are covered 

 with ivy. Walking close up to the dike, I found that the yellow 

 tufa was full of small, (occasionally intermixed with large) sharp, 

 irregular fragments of basalt, while the red generally contains 

 larger masses, and is more layer-like in its deposit. This slip has 

 evidently occurred from the giving way of the tufa, beneath the 

 basalt, covered by the sea. The euphorbia dendroides, the ruta 

 graveolens, and a new species of gnaphnlium, grew close to the 

 beach, the latter extending itself up the rocks''. In the pores of 

 the nodules of basalt which had been rounded and thi-own upon 

 the beach by the sea, I found the galeolaria elongata, and the 

 vermilia bicannata, both of which have been hitherto referred to 

 New HoUand alone *^. The latter was of the most beautiful rose 

 colour, gradually passing into white ; its double keel, sometimes 

 indented, and its aperture with two teeth, would not admit of 

 any doubt ; but the animal, as well as that of the galeolaria, had 

 perished. Without a minute examination I should have oro- 



' Genus Gnaphlium, an tomentosum ? Floribus flosculosis luteis, (foeminei herma- 

 phroditis mixti) corollulis integris, vix manifestis. Calyce persistente, imbricato, 

 ventricoso, squamis acuminatis, scaiiosis, luteis. Pappo capillare. Receptaculo 

 alveolato nudo. Caule suffruticoso racemoso. Foliis alternis, ovatis, oblongis. 

 Floribus terminalibus corymbosis. Planta tola, valde tormntosa, canascens, odorata. 



' Bowdich's Elements ofConchology, Part II. 



