— 69 — 



applied to those under consideration. About ten or 

 twelve miles further north, at a place called Ambo- 

 divato, I afterwards found several other craters on a 

 large comparatively flat-topped tanety, one of which 

 was much greater in dimensions than any of those 

 described above. All these volcanoes being so near 

 the great Ankay and Antsihanaka plain, the bed of a 

 former lake, one feels curious to know whether others 

 may not exist along its margin or within a pro- 

 ximate distance of it. Indeed at Ankeramadiuika 

 and Andrangoloaka, about a day south of Am- 

 bohid ratrimo, are to be found what appear to be 

 fragments of lava of volcanic products and probably a 

 proper search would lead to the discovery of volcanoes 

 near these places. Perhaps it may be mentioned here 

 that in a stream, in the forest near Ambohidratrimo, 

 there is found a kind of opal in which are contained 

 numerous Zeolites. In the same stream there are stones 

 of hasalt, while the forest itself covers what appears 

 chiefly to be decaying granite and vertically inclined 

 gneiss." 



By the above notes we may infer that the Grreat 

 African Island was one time disturbed by volcanic 

 eruptions in the central Province of Imerina : but now 

 the Island appears to be free from volcanic distur- 

 bances. 



James Fokestbr Anderson. 



