222 NERBUDDA DISTRICT. 



which Col. Sykes speaks in the Deccan; but even in our area, several 

 such escarpments occur, and the description contained in the above pass- 

 age is (with this reservation, of less height in the hills) applicable to 



much of the trap country of our map. With 

 Lithology of Trap. . ~ 



regard to the mineral structure and composition of 



the trap flows the same author found that " it varied exceedingly in 



" short distances even in the same stratum." — " The basalt in one 



" continuous bed may pass several times from close-grained compact 



" and almost black, to grey amygdaloidal, and externally decompos- 



" ing." 



Col. Sykes states, that he, as well as all previous observers, had failed 



to detect satisfactory evidence of craters, or even 

 Centres of eruption. . 



of their probable sites ; nor have we, in our portion 



of the trap-area, been more successful. No apparent volcanic centre can 

 be pointed to, from which any, or several of the many flows have proba- 

 bly proceeded. The only approach as yet made to the solution of this 

 problem may be found in the unequal distribution of the evidence of the 



. ± . A1 _ intensity of igneous action in certain areas, this 

 Approximation to the J ° 



discovery of these. intensity being estimated both from its mechanical 



and chemical point of view. For we can show that in some places the 



intrusion of the trap has been accompanied by a minimum of disturbance, 



that it has filled cracks in the sedimentary rocks, and overflowed their 



beds, without affecting their texture (chemically) or being itself acted on 



by their vicinity. Whereas in others, the reverse of all this is the case ; 



beds have been shattered ; fragments of them enclosed ; and both the 



sandstones and the traps much altered at their junctions. 



Perhaps careful and widely extended observations of these phenomena 



_,, . .. might guide into the discovery of volcanic centres, 



Closer examination re- to & J ' 



1 msite - but, as already stated, the trap area having only 



been cursorily examined, we have little to advance on a subject em- 

 inently requiring great caution both in observing and in drawing conclu- 



