VOLCANO OF ANKARATRA 221 



bourhood of Itasy, we have to pass to the westward of the great 

 massif of Ankaratra ; and the summits of this mountain^mass 

 being the highest points in the centre of the island, a 'short 

 space must be devoted to a brief description of it. From the 

 capital, Ankaratra is the most prominent object in the land- 

 scape to the south-west, rising by easy gradients to about twice 

 the elevation of the general level of Imerina, and three or four 

 points showing distinctly against the sky, although they are 

 from forty to forty-five miles distant. The highest point is 

 called Tsiafajavona (" that which the mists cannot climb "), 

 and is eighty-six hundred and thirty-five feet above sea- 

 level. There is no doubt that the whole mountain is an 

 ancient volcano, for the rock which has been poured out as 

 lava from it is a black olivine basalt. One peak, to the east, 

 consists of mica-trachyte ; and at its northern foot there is an 

 exposure of augite-andesite rock. " Seen from Antananarivo, 

 the mountain of Ankaratra seems to be one almost uniform 

 mass, but when actually there, it resolves itself into deep 

 ravines, enormous spurs, conspicuous peaks, and isolated or 

 continuous mountain masses. The spurs, which run out like 

 so many fingers in all directions, and to great lengths from 

 the main body of the mountain, do not represent so many 

 lava flows, but have been formed by the numerous streams 

 which have excavated the deep and wide valleys between 

 them." 



The amount of lava that has issued from Ankaratra, says 

 Mr Baron, is truly astounding, reaching in places to a depth 

 of twelve hundred to fourteen hundred feet, and occasionally 

 to as much as two thousand feet. Occasionally the basalt 

 assumes a columnar form ; but everywhere the surface of the 

 lava is decomposed into soil. This, and the apparent absence of 

 all craters on and around the mountain, seems to point to a 

 long period having elapsed since the volcano was active, probably 

 several centuries. When on the highest point of the moun- 

 tain, there appear to be two ranges of summits ; which lie in 

 the form of a cross, the intersection being marked by a small 

 cone. On the south-western slopes are considerable remains 

 of forest, which probably in former times covered a large pro- 

 portion of the present bare highland of the interior of Mada- 

 gascar. It is by no means easy to get natives to go with one 



