OF WESTEEN STND. 245 



included in the collection of Echinoidea from the Ranikot series of Sind, and referred 

 to in Part II. of this work. The evidence respecting the examples in question is very 

 strong against their belonging to the B,anikot series at all, and until further confirma- 

 tion is forthcoming we do not feel justified in counting them as members of that fauna » 

 or in basing such generalizations upon their presence as their recognition as Ranikot 

 species would obviously demand. The forms referred to are Bhynchopygus Calderi, 

 Bhynchopygus pygmceus, Hemiaster digonus, and Metalia Sowerhyi ; and the following 

 facts respecting them are very significant. In each case the forms were represented 

 only by solitary and very badly preserved specimens, excepting M. pygmceus, of which 

 there were two or three. All the examples of these four species in the Ranikot collec- 

 tion were from one locality, viz. N.E. of Petiani. On referring to the memoir on the 

 Geology of Western Sind by Mr. W. T. Blanford, F.R.S. *, we find it mentioned that 

 two outliers occur north-east of Petiani, the age of which is not clearly determined ; 

 and the resemblance of the rock, in one of them at least, to a sandstone occurring at 

 Jungshahi, age also not clearly determined, is remarked on [op. cit. p. 14.6). 



In reference to this question, it is of interest to note incidentally that two of the 

 four species above cited have been found at Jungshahi, in strata of the Khirthar series, 

 at the localities numbered by the Surveyors ^^ and ^^. 



If it were the case that the doubtful specimens under notice were obtained from 

 the outliers mentioned by Mr. Blanford, it might be inferred, on the palseontological 

 evidence, that the outliers were of Khirthar age ; and in the event of these specimens 

 having been picked up on the surface, which would appear very probable from their 

 weathered condition, we are still of opinion that they were derived from Khirthar 

 beds f. 



From the foregoing summary it will be seen that not a single species is common to 

 the Khirthar and Ranikot strata, if the doubtful forms above referred to are excluded 

 from the list. 



Attention has already been drawn to the specialized and well-marked character of 

 the Khirthar fauna as compared with that of the Ranikot ; and this becomes still more 

 patent and conspicuous when the lists of genera contained in the respective measures 

 are placed side by side. Excluding the doubtful forms previously mentioned, the 

 Ranikot fauna comprises 24 genera of Echini and that of the Khirthar 25 genera ; of 

 these only 9 genera are common to the two series of strata. It will thus be seen that 

 the Khirthar fauna is a remarkably isolated assemblage of forms in relation to the 

 underlying fauna of its own area. 



* Mem. Geol. Sarv. India, vol. xvii. 



t Mr. Blanford, with, -whom we have corresponded on the subject, is fully disposed to concur in this latter 

 supposition. He also informs us that at a locality about 20 miles further south he was enabled to draw a 

 line at the base of the Khirthar beds, and to separate them from the Eanikot, on account of the presence of 

 RTvynchopygus Calderi in the former — a species which, in his experience, is characteristic of a zone at the base 

 of the Khirthar. In the locality mentioned the two groups could only be distinguished by fossils, the mineral 

 character being similar. If, as is probable, there is the same similarity north-east of Petiani, it can easily be 

 imagined that fossils might have been obtained from supposed Eanikot beds, which were really of Khirthar age. 



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