278 



Memoir on (lie Geology of (he 



whole length of the mass, in a nearly horizontal direction, although 

 traversed in the same way as the strata by the fissures, has not suffered 

 any fault or displacement. 



After passing the long valley, the hills to the left have numerous 

 masses of basalt and of basaltic hornblende, either as overlaying rocks, 

 at their summits, or forming black and naked convexities on their 

 sides. And now, nearly all the hills that branch off from a huge 

 mountain mass, a few miles eastward of the termination of the long 

 valley, stretching N. E. and S. W. and ending at the abrupt limits of 

 the Koondahs, near the Devil's Gap, are basaltic, giving to them a form 

 and aspect quite different, not only from those of the Neelgherries, but 

 from those of the first tract of the Koondahs, and even from those which 

 flank this chain of basaltic hills on both sides. Their contour, although 

 rounded in a certain degree, does not proceed from the decomposed 

 rock, as in other parts, but from the enormous, convex, bleak and 

 black masses of trap, which form them, and on which neither grass nor 

 trees grow ; in short they clearly show, even at this distance (two or 

 three miles), the diversity of the rock they are formed of. It is nearly 

 all trap, to be described hereafter. 



Resuming our itinerary — At the end of the long valley the basalt is 

 seen in dykes, as in the bed of the torrent, or capping the hills 

 (No. 135), From this place until we reach-New England, all the rocks 

 are granitic, with a good deal of mica (No. 136), in many parts decom- 

 posing, not into lithomargic earth bat, into a sandy soil mixed with a 

 little clay. In the bed of the river which runs at the eastern end of 

 New England, the pegmatitic rock, which is now the predominating 

 surface rock for many miles west, is seen intersected by dykes of 

 basalt, which ramify through it in all directions (No. 137). When I 

 said just now that pegmatite succeeded granite, I meant on the right 

 of the road, chiefly; since the hills to the left are intermixed with a 

 good deal of trap. The little insignificant flat of ten acres, which has 

 been dignified with the name of New England, is a small barren spot, 

 on which I doubt whether there is room for a race course ! In the 

 road which passes through it there are many masses of pegmatite, level 

 with the ground, intersected in all directions by numerous diramations 

 of basalt, similar to those just passed. Near this place the basaltic 

 dykes have great thickness, and many of them are decomposing, and 

 decomposed, into the yellow ferruginous clay (No. 138). From this 

 place to the Devil's Gap, the country to the right is formed of pegma- 

 tite, and, in some places, mica being added, it passes into large grained 

 or porphyritic granite (No. 139.). 



It is as we approach the Gap that the direction of trap may be seen, 

 forming a black and naked chain of hills, of which the one to the left 

 of the Gap is the western termination. Of the two hills, forming this 



