206 NERBUDDA DISTRICT. 



The limits of the area under description at present do not permit us 

 to follow Mr. Hislop in all his researches, which extend far beyond our 

 district. But so far as his views relate to that district it seems needful 

 to offer a few remarks. 



Mr. Hislop states his belief that the aniygdaloidal trap which underlies 

 the " intertrappean" sedimentary rocks was liquid subsequently not only 

 to the deposition of that rock, but also to the consolidation of the upper 

 trap, both of these having apparently been broken up by it : still he thinks 

 it probable that the lava in both positions belonged to the same eruption, 

 the upper portion of it having cooled first. We would only repeat, that 



necessarily limited. Nor were there within the districts visited so many localities, where 

 these " intertrappean " beds were visible, as there are in other parts of the country. The 

 survey collections have, however, been enriched by many organic remains from these beds, 

 presented by the Rev. S. Hislop of Nagpur, and altogether they include a fair series of 

 shells &c. representative of the group. In the examination and description of these much 

 progress had been made, and it was intended to have given here a brief diagnosis of all the 

 species we possessed, together with figures &c. Meanwhile, however, Mr. Hislop himself 

 having both sent, and taken with him, to England a large collection of these organic remains 

 has devoted his attention to their description and has laid before the Geological Society 

 of London the results, the abstract of which has reached us while this was passing through 

 the press. In the Journal of that Society, the description &c will appear at full. Mr. 

 Hislop's collections being, probably, far better than those to which we have access, we have 

 determined to withhold for the present, all specific descriptions of the latter, it being far better 

 that a few weeks' delay should occur than that the same shells should be described under 

 different names. We have therefore, placed all our drawings &c. at Mr. Hislop's d sposal. 



The condition in which these remains usually occur is particularly unfavorable for the 

 accurate determination of species. In some few localities the shell itself has been preserv- 

 ed, but it is generally exceedingly difficult to extricate it, in consequence of the cherty and 

 splintery character of the mass in which these remains are embedded. But in the majority 

 of cases, little is found but a sharp silica cast, which, although sufficient to establish the 

 identity of one specimen with another, affords no sufficient or reliable characters for de- 

 tailed description. 



As mentioned above, only some of the localities from which our collection contains shells 

 have been visited by the officers of the Geological Survey. The most easterly of these was 



