1859.] 



H1SL0P GEOLOGY AND FOSSILS OK NAGPCTt. 



157 



Here we see nodular trap of about 14 feet thick in the central 

 and more remote part of the sketch, overlying the freshwater de- 

 Fig. 2. — Section in a ravine between TelanMiedi and Ndgpur. 



u. Nodular trap-rock ; from 4 to 14 feet thick. 



b. Freshwater-rock ; 1 to 3 feet thick. 



c. Amygdaloidal trap, with interspersed bands of altered freshwater-rock. 



posit, the top of which only is visible, and which extends 3 feet 

 downwards without interruption. In the foreground on the left 

 bank of the stream, or on the spectator's right hand, the same trap 

 reaches no greater thickness than 4 feet, while the sedimentary 

 rock on which it rests is less than a foot thick, the remainder being 

 dispersed in the form of pale bands, sometimes running into each 

 other, through the body of the volcanic rock, which in these cir- 

 cumstances has assumed chiefly a soft vesicular structure. An ex- 

 amination of this spot would, I think, suffice to convince any geologist 

 that the trap in its amygdaloidal form must have been the instru- 

 ment of this scattering of the deposit, and that consequently it must 

 have been injected after the deposit accumulated at the bottom of 

 tin- hike. 



Whether the amygdaloid is a subsequent eruption to the nodular 

 trap, as I once supposed, is not so certain. All that the phenomena 

 which I have observed Bhow, is that it was probably liquid after the 

 nodular part was consolidated ; and this may have been the rase in 

 consequence of the upper portion of the lava cooling first, although 

 both it and the Lower portion were erupted at the same time. To 

 illustrate this I subjoin a third section exhibiting the relation of the 

 rocks lying in a line drawn from the Artillery Lines of Takli south 

 to the Nag River. 



deposit, the upper part of i& probably remaining in its original position imme- 

 diately under the " globular concentric bum It," and the n-! being dis|>ersed hv 

 the roloanio rook, u in our section. Sometimes the Beams originating from tin* 



deposit lire more .la\c\ and siliceous in their elmni.-t.r. unci then we have mi 



abundance of jasper, bloodstone, or oherty Bint s. H . June --. 1869 



