INTRODUCTORY. 15 



N. guettardi, N. granulosa, and N. exponent may perhaps belong to a 

 rather higher horizon, and N. garansensis mark, as in the neighbourhood 

 of Dax, the latest period of existence of these animals. 



At the same time, some of the fossils of Sind are arranged, in accord- 

 ance with the nummulites found associated with them, in three categories, 

 the two lower of those already mentioned being united, and a third being 

 formed of those fossils with which no nummulites are found, it beinsr 

 considered uncertain whether the last is higher in the series than the 

 two others, or intermediate. It is, however, observed that the absence 

 of nummulites in specimens of fossils is merely accidental, and insuffi- 

 cient to prove that such specimens are from a distinct bed. Lists of the 

 species found associated with different forms of nummulites, &c, are 

 given, and the majority of these are correctly classified and have been 

 found in the positions assigned. Of course Messrs. D'Archiac and Haime 

 were unaware that, besides the beds without nummulites overlying the 

 nummulitiferous formations, there were other beds at a lower horizon 

 in which nummulites were scarce or wanting. They appear, moreover, 

 not to have attached sufficient importance to Vicary's recognition of a 

 formation without nummulites above the other marine beds. 



The works already quoted contain, with one exception only, all the 



information of any importance with reference to 



Other writers. 



the rocks of Western Sind before the commence- 

 ment of the survey. The exception is the recognition of distinctly 

 miocene fossils in the Sind collections by Professor Martin Duncan and 

 Mr. Jenkins. The following is a list, arranged in order of time, of, so far 

 as is known, all papers and works in which the geology of any part of 

 Western Sind is described from observation, The list might of course 

 be indefinitely extended by quoting every writer who published an 

 account of his travels in any part of Sind, or who referred to the observ- 

 ations of others. There are, for instance, several itineraries in the 

 Transactions of the Bombay Geographical Society, but none of them add 

 to the geological knowledge of the country. It may even be questioned 

 whether some of the writers quoted below can be said to have described the 

 geology of the province. 



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