430 Geological Sketch of the Neilyherries. [Aug. 



dispersed through the rock, but, as it were, in nests (No. 44). This 

 rock is very like the specimen in your museum from Norway, mark- 

 ed " large garnets in hornblende." Indeed, I think that there is 

 great analogy between the sienite zirconienne of Norway and this 

 rock of the Neilgherries (No. 45). I remarked in one place of the 

 Dodabetta group some veins containing quartz and garnets ; the last 

 in the granular or resinitic form (No. 46). 



Before dismissing the subject of the hornblende rock, I must 

 remark, that although this primitive greenstone is occasionally seen 

 on the summit of some hills, in general it occupies the declivities or 

 the lowest parts of them ; and it often assumes a brilliant, laminar 

 crystallization, being then exclusively formed of hornblende (No. 47). 



I have seen it passing into hornblende slate at the foot of the 

 Neilgherries, at the bottom of the Kunur pass. Here its strata 

 dip to the east, and I am informed, that the same stratified rock is 

 found at the foot of the same group of hills, to the west, the strata 

 in that place dipping west. It is in those places that this rock occa- 

 sionally passes into sienitic gneiss. 



These are all the rocks I have met on the Neilgherries, of which 

 their extensive plateau is formed, and the relative position of which 

 can often only be surmised, on account of the thick covering of soil, 

 and of red earth, which conceals the rock generally. 



I must in the last place notice the numerous basaltic dykes which 

 burst up through all these rocks indiscriminately, without however 

 overlying them, except in one situation ; and even there the basalt only 

 forms a small ridge, flanked by the fundamental rock. 



I shall describe briefly those places where I have had opportunity 

 of examining this rock ; and first, that in the Kuniir pass. Not more 

 than a mile from the bridge down the pass, and just below the village 

 of Kunur, in the road, many of the blocks which have been blasted, 

 are traversed by a dyke of basalt. In the little ravine close to the 

 road, the dyke is seen in situ through the masses of granite in the 

 jungle. This dyke divides in two or three branches, inclosing betwixt 

 them the granite ; then it is seen continuing in a north direction, till 

 close to the huts of the village. The projecting masses through the soil 

 indicate the direction of the thick dyke, which in a place near the road 

 is divided in well marked prisms above the granite (No. 48). 



This basalt is very compact ; has a dull, even fracture ; but in one 

 portion of the dyke, I had the opportunity of observing, that the 

 part which was in contact with the granite had the appearance of a 

 crystalline hornblende, which passed into compact hard basalt to- 

 wards the centre of the dyke. I also remarked, that where the dyke 



