Chap. IV. § 3.] ironstone shales. 75 



angular fragments, and in which seams of argillaceous iron ore, vary- 

 ing in thickness from 2 inches to a foot, occur at irregular intervals. 

 Throughout the area represented upon the map, as occupied by these 



Uniform mineral cha- beds > the argillaceous carbonate of iron is com- 

 rac mon, but it appears to be both more abundant 



and of better quality towards the top than near the base of the 

 series. 



Though sections, even the smallest, are rare, fragments of the iron- 

 stones generally occur upon the surface so abundantly as to mark well 

 the area covered by the out-crop of these beds. They appear, despite 

 their softness, to resist atmospheric denudation better than the harder 

 grits or sandstones which rest upon or underlie them, for the ironstone 

 shales form a high ridge, stretching across the country. This is pro- 

 bably due to their resisting the corroding action of water containing 

 carbonic acid better than the felspathic ingredients of the sandstones. 



Sandstones occasionally occur, especially towards the base of these 

 beds. On the banks of the Barakar, at Bagonia, 



Section near Bagonia. 



the following section is seen : — 



(Descending.) 



Ft. in. 



1. Ordinary ironstones and shales, containing a few thin bands of 



micaceous sandstone. 



2. Rather coarse felspathic and micaceous sandstone, thickness not 



quite certain, as a slight throw occurs, but probably within a 

 foot or two 



3. Hardened carbonaceous shale 



4. Trap, intrusive 



5. Hardened carbonaceous shale 



6. Blue micaceous sandy shale 



7. Blueish thin-bedded micaceous sandstone 



8. Hard massive felspathic sandstone ... 



9. Coarse felspathic sandstone, micaceous and false-bedded 



10. Shaley micaceous sandstone, passing down into 



11. Black carbonaceous shales and ironstones, Lower Damudas 



Total ... ... 89 3 



