APPENDIX. No. VI. 487 



are told by this author, tliat the name given to it by the Portuguese, is ii 

 Presidio (the fortress), and that tlie natives cdll it " Afaoponffu,'" — a word 

 which, making but httle allowance for national difference of expressing the 

 same sound in writing, is pretty like that of " ATwangooi" synonymously 

 added to the sketch given of the Fetish rock by Captain Tuckey. 



Boka M'Bomnia, according to tiie same gentleman's account, consists en- 

 tirely of sliistus; but his own specimens from the S., S.E., N.E., and S. W 

 parts of that island, are stratified granite or gneiss, in which the feldspar exists 

 in very small proportion, and which, on the S.W. side, passes into a beauti- 

 fully resplendent silvery variety, stained, towards the surface of the blocks or 

 separated pieces, by brown iron ochre. It is in the variety of this gneiss from 

 the last-mentioned part of the island, that laminar particles of a dark brown 

 colour are seen, some of them exhibiting traces of the regular octohedral form, 

 and which appear to be an iron oxydule. Tiiere is also, among the specimens 

 from Boka Embonuna, a friigment of primitive green-stone witli embedded 

 garnets. 



The specimens from tlic creek of Banza IM'bomma exhibit a mixture of fine 

 granular liornblcnde and quartz ; some of them are real hornblende-rock, and 

 contain disseminated garnets. These specimens, among which there are also 

 some varieties of reddish massive quartz, not unlike milk-quartz, were col- 

 lected by Mr. Tudor. 



Besides these primitive rocks, and those from Chesalla, near the Banza, 

 which latter affords two varieties of gneiss with black and with yellow mica, 

 we have, from the same neighbourhood, and particularly from tlie Chimoenga 

 cliffs, a few specimens of sandstone : it is coarse-grained and ferruginous ; its 

 colour is grayish, and yellowish, with here and there some purplish specks ; and 

 it appears to belong to the oldest formation of this reck. The plain on which 

 the banza is situated, is covered by a bed of clay, which, according to a label 

 accompanying the specimens, is two feet thick. It is of an a^h-gray colour, 

 and perfectly plastic. 



The quartz mentioned by Captain Tuckey and Professor Smith, as being 

 Ibund in large masses, on the summit of Fidler's Elbow, belongs to the variety 

 called fat-quartz : the fragments have mica adhering to them, and are here and 

 there stained of a blood-red colour. Some specimens of brown-ironstone, 

 massive and friable, have likewise been found on this hill. A ticket written by 



