1836.1 



of the Southern Makratia Country* 



457 



blende ; but it is very seldom that all these ingredients are found asso- 

 ciated in one specimen. Sometimes one ingredient, sometimes another, 

 is wanting, which produces a very great number of varieties. By far 

 the most common is that composed of quartz, felspar, and hornblende,— 

 the sienite of Werner. The felspar is in some instances white, in 

 others red. A great part of the Indian peninsula, therefore, consists of 

 a rock precisely similar to that found in the famous quarries in Egypt 

 and it has the same geognostical situation j for we are told by Daubuis- 

 son* that the latter, like the Indian rock, is associated with granite. f 



The ingredients vary very much in their proportions and colour ; 

 and thus produce varieties that occur within a short distance of each 

 other, in the same lamina. One variety is sometimes found passing 

 imperceptibly into another, penetrating it in the form of a vein, or im- 

 bedded in the form of a nodule. 



A very interesting variety is found associated with the granite at 

 Roan, in the Darwar district^. It consists of a very dark red felspar, 

 with small disseminated crystals and minute veins of quartz ; and, 

 what is curious, there are numerous small vesicular cavities throughout 

 the felspar, some of which are lined with very minute crystals, appa- 

 rently of chlorite. It would be interesting to ascertain the exact rela- 

 tion which this rock bears to the granite, a point which I myself had 

 not an opportunity of examining. 



A very beautiful rock is found associated with the granite at Gudjun* 

 dergbur. It is a sort of greenstone porphyry ; the basis being green- 

 stone, and containing large crystals of red felspar. 



The Indian granite is generally small granular. I have only seen 

 one specimen of large-grained granite in India, which had been brought 

 from Mysore, and was composed of felspar, quartz, and mica. 



At the falls of Garsipa there is a variety of granite, which differs 

 from the common granite of India. It is not so old a granite as the 

 latter ; is composed of small grains of white felspar, quartz and mica ; 

 has, in some instances, a slaty appearance ; and is associated with 

 gneiss and hornblende schists. These rocks, being perfectly bare, can 



* Traite de Geognosie, torn. 11. p. 20. 



f This is, consequently, the sienitic granite of Macculloch and Dr. 

 Benza, being associated with primary rocks, and composed of the 

 minerals specified above ; sienite may be similarly constituted, but is 

 of a later geognostic position, and associated with porphyries, with 

 greenstone, basalt, and the other overlying rocks of the trap forma- 

 tion. It is quite essential that this perspicuous and simple distinction 

 should be observed.— Editor Madras Journal, 

 i I am indebted to Walter Elliot, Esq. for the specimens of this rock which I possess. 



