ChA1\ IV. 1.] METAMORPUIC ROCKS. O'J 



iron beds is remarkably perfect, especially some of the numerous hornblen- ^ 

 die beds to the east of Namkul. The great curve, or rather series of 

 curves, is due to a pecidiar elevation of the strata, which were then 

 planed down partially by some g-igantic denuding agency, acting 

 through periods of immense duration. The total thickness of strata 



which appear in this great curve, measuring from 

 of section.^ '^ ^'^ ^^^^ the soutli side, on which the succession is most 



clearly displayed, to the centre of the KolymuUays, 

 where the heart of the curve appears to be, must be veiy greato The 

 angle of dip may safely be assumed on the average to be 60°, the angles 

 taken at three of the most prominent points on the periphery of the 

 curve being 65°, and the beds in many parts dipping at angles as high as 

 75°. A section from north to south across the Tullamullay, and con- 

 tinued across the KolymuUays, would cut across one or more of the cm-ved 

 beds occupying a very high place in the whole series, and show very 

 nearly if not the entire number of beds. This section, extending from a 

 point about 2 miles east of Totium to the magnetic iron bed north of 

 Wallalputty, on the KolymuUays, a distance of 18 miles, in a direct line 

 across the out-crops of parallel strata dipping north at an angle of 60° 

 would represent a thickness of some 50 to 55,000 feet of solid 

 rock, or, if a liberal allowance is made for undue attenuation of the strata 

 owing to a sliding movement against each other, the thickness may safe- 

 ly be taken as varying from 40 to 45,000 feet. This must not of course 

 be considered as the thickness of the whole series of metamorphic rocks 

 but only of that portion of the beds forming the series included in this 

 giant curve. 



The number of iron beds belonging to this series may be set down as 



three, though really there are several more, but 

 ^"""''^siier ^'^ '^ tl^ese latter are shown to a very small extent, and 



are probably not continuous, but die out very soon 

 after they become obscured by the overlying soil. The principal beds 



( 285 ) 



