CHAP. 8.] GENERAL SUMMARY OF FORMATIONS. 85 



dykes of the darker and older trap ; the latter situations evidently being 

 lines of weakness where newer intrusions might be expected to occur. 



Associated with these rocks are the laterites of Kutch, but whether 

 as derivative beds, or as altered or original traps the evidence to be obtained 

 from their occurrence in the field is not of itself sufficient to show. This 

 form of rock has not certainly been found intrusive in dykes, but is 

 closely associated with the newer volcanic beds or flows, and although beds 

 of it occur for some distance upwards into the lower tertiary deposits, it 

 has never been found to contain a single organism. 



Nothing has been found to prove these later volcanic and lateritic 

 beds unconformable to the older stratified traps, and though both are 

 azoic, there are associated with them certain shales which are in places 

 crowded with the forms of leaves belonging to the two great vegetable 

 classes, but which have not been observed to contain any marine organisms. 

 Very shortly succeeding these, however, the marine tertiary fossils 

 appear, Ostrea and fish being among the earliest forms. 



The lowest tertiary beds succeeding the traps (these being believed 

 themselves to be of early tertiary age), including the 



Tertiary. 



nummulitic group, appear to have been deep-sea 

 deposits ; and the succeeding beds again afibrd evidence in their leaves 

 either of lacustrine or estuarine conditions or of vicinity to the maro'in 

 of the land. Marine beds, locally abounding in fossils, succeed to 

 these, the fossils indicating frequently the presence of littoral regions ; 

 and then a break and unconformity occurs, the newest or upper tertiary 

 beds having either a strongly shore-like or approximately recent aspect. 

 Marine fossils are still found ; but in much of this upper part of the 

 formation fossils of any kind are absent. 



The overlying alluvium and sub-recent deposits, except in their most 



. superficial portions, contain no evidence as to the 



Alluvium. 



conditions under which they were accumulated ; 



and where they do enclose organisms these are, as usual, terrestrial and 



recent shells, &c. 



( 85 ) 



