110 GEOLOGY OF TRIClIINOrOLY, &C. [ChAP. V. 



The country between the two corresponding beds of magnetic iron, 

 in other words^ along the line of shift, is covered by thick soil, and no 

 signs of any fault-breccia were met with. 



Northward of the Shevaroys and the Tainandamullay ranges, the 



Huroor and Aclamau- southern part of the Baramahal plateau terrace is 



CO a scries. traversed by a rather remarkable series of large 



trap-dykes having a north-westerly course. Exactly speaking, they run 



from south-east by east to north-west by west. 



The series is composed of five dykes, which, though in many places 

 they may be tracked for miles, are yet here and there hidden for consider- 

 able distances either by accumulations of soil, or else by jungle. They 

 generally project well above the surface of the country, and are very 

 conspicuous, sometimes forming ridges of no small magnitude. 



The southernmost of the dykes crosses the northern end of the 



Munjawaddy pass from the western flanks of the 

 Courmullay dyke. . . 



Tainandamullay j is then lost for a distance of 4^ 



miles, but re-appears and crosses the Courmullay, and also the broad valley 



through which the railway reaches Mullapooram station. 



The Durmahpoor mountains are crossed Ly the dyke in great force, 

 but it is again lost for several miles under a thick spread of cotton soil 

 north-east of Adamancotta. It re-appears immediately west of the 

 Salem and Bangalore road, and after a further course of 4 miles, 

 extends beyond the limits of the country under survey. Including the 

 breaks, the length of this great dyke is about 28 miles. 



About 5 miles to the north is another large dyke, following a very 



nearly parallel course for 23 miles, Avithout any 



Moonimiillay dyke. . , , , i t 'i +i ^ -4. 



important breaks. Liike the lormer one it crosses 



the Durmahpoor range, just south of the Mookanoor Trigonometrical- 

 station hill. 



The third of this series is a smaller dyke running nearly parallel 

 with the foregoing, with several discontinuities however. 



( -332 ) 



