APPENDIX. 



909 



the craters surmounting the larger islands are of immense size, and 

 they rise to a height of between three and four thousand feet. Their 

 flanks are studded by innumerable smaller orifices. I scarcely hesitate 

 to affirm, that there must be in the whole archipelago at least two 

 thousand craters : these consist either of lava and scoriae, or of finely- 

 stratified sandstone-like tuff. Most of the latter are beautifully 

 symmetrical ; they owe their origin to eruptions of volcanic mud 

 without any lava." A. small jet of smoke was seen curling from one of 

 the craters in Albemarle, and eruptions are known to have taken place 

 in modern times. 



Great parts of the surface of most of the islands are broken fields of 

 black basaltic lava, thrown into the most rugged waves, and crossed by 

 great fissures, and covered by stunted sun-burnt brushwood. But 

 while the lower parts of the islands are very sterile, the upper regions, 

 at a height of a thousand feet, possess a damp climate, and a tolerably 

 luxuriant vegetation. The commonest bush is one of the Euphorbiaceae, 

 and with an Acacia, and a great odd-looking Cactus, are the only trees 

 that afford any shade. Coarse grass and ferns abound in the\ipper 

 parts, but no tree ferns, nor any of the Palm family, were observed. 

 Large land tortoises, in prodigious numbers, are the principal animals, 

 and form the staple article of food to the inhabitants, who are nearly all 

 people of colour banished for political crimes from the republic of the 

 Equator. 



The rocks on the coast of Albemarle Island abound in great black 

 lizards, between three and four feet long, belonging to two species ; one 

 of which is aquatic, and feeds on sea-weeds, the other is terrestrial. 

 "They are allied to the Iguanidae, (]) and belong to the genus Arnbly- 

 rhynchus, which is confined to this Archipelago. They have long tails, 

 flattened laterally, and all the four feet are partially webbed. Most of 

 the other organic productions are found nowhere else : there is even a 

 dissimilarity in those of the different islands : yet all show a marked 

 relationship with those of America, though separated from that continent 

 by an open space of ocean between 500 and 600 miles in width. Of 

 terrestrial mammals, there is only one that can be considered as indige- 

 nous, namely, a mouse ; and even this is confined to Chatham Island, 

 the most easterly of the group. Of land birds, twenty-six species were 

 obtained, 1 albut one peculiar to these islands. Of the order of reptiles, 

 in addition to the Amblyrhynchi, there are one small species of lizard of 

 a South American genus ; one snake ; and of marine turtles, or chelonia, 

 more than one species; and two or three of tortoises, yo batrachian 

 reptiles, as frogs or toads, were observed. The Amblyrhynchi are very 

 abundant, and the terrestrial species especially, in some places; in 

 James's Island their burrows were so numerous, that it was difficult to 

 find a spot free, on which to pitch a tent. The two species agree in 

 their general structure, and in many of their habits; they have not 

 that rapid movement so characteristic of the genera Lacerta and Iguana, 

 They are both herbivorous, although the kind of vegetation on which 

 they feed is very different ; the land species feed on the succulent 

 Cactus, and the aquatic species on sea-weed. Mr. Bell has given 



