262 



Memoir on the Geology of the 



[Oct. 



All the above mentioned stratified rocks are overlayed by an enor- 

 mous unstratified black mass, the composition of which approaches 

 hornblende porphyry; although in some portions it loses the garnets 

 altogether, or, at least, they become very rare, and the quantity of 

 felspar increases in proportion (No. 52). This superincumbent rock, 

 when decomposing, exfoliates concentrically, passing through the usual 

 stages of that process, observed in rocks of similar composition on these 

 hills (No. 53). The mass, to the right of this large block, overlays 

 nearly the same strata as the last ; but the soil in this, reaching high- 

 er than in the former, prevents the sight of the colophonitic rocks 

 which underlay it. All the rocks scattered on, or implanted in, the soil 

 about this place, are either of quaternary granite or of hornblende rock. 



As I said before, rocks being unfrequent, in the lower parts of the 

 whole extent of Kaitee Valley, except some loose blocks at the foot of 

 the two chains of hills, which confine it, I think that to have a correct 

 idea of the rocks of this locality, we must describe these two ranges of 

 hills separatel)' - . 



Going from Ootacamund towards Kaitee, and reaching the last 

 houses of the Cantonment, at the little gorge, a path is seen to the left, 

 which leads to the summit of Doodabetta ; after ascending a few hundred 

 yards, to the right we see three small villages, near the ravine, through 

 which a road leads to the gap, between the summit of Doodabetta and 

 the southern branch of Kaitee, which ends in the blur! precipice of the 

 pass. Passing a mile beyond these native villages, called Mantoo, we 

 see, close to the road, and extending further along the declivity of the 

 till to the left, large masses of cavernous, hsematitic iron ore, similar 

 to that of Scotland Valley (No. 54). This bed is but a few yards 

 thick, and the rock, although in general scabrous and porous, is com- 

 pact and with a glimmering fracture in some of the blocks; then 

 assuming the appearance of real heematite (No. 55). The direction 

 of this ore is N. and S. and it does not seem to extend very far either 

 way ; being flanked, particularly at the eastern side, by a beautiful 

 hornblende porphyry with garnets (No. 56), which, however, on the 

 western side, losing the garnets, becomes hornblende rock (No. 57). 



Arriving at the gorge, where the two ramifications of the Kaitee 

 group divide, and leaving Doodabetta to the left, we follow the eastern 

 range of Kaitee, the precipitous faces of which look into Kaitee, 

 Valley, and we see that the first of them, particularly its summit 

 is formed of granite, abounding with quartz ; the other minerals being 

 mica, felspar, and a few garnets (No. 58). The colour of this granite is 

 similar to the feuille morte of the Doodabetta group (No. 53), and, like it 

 is traversed by, or passes into, pegmatite (No. 60). In the next hill, the 

 western precipitous face is formed of pegmatite, which, in this place 

 is flanked by granite, abounding in mica (No. 61). 



