COBALLIFEROITS SERIES OF SEND. 



207 



a succession, on the same area, of marine beds over the terrestrial 

 and freshwater series, if the fossils of the upper strata resemble 

 those of the deeply seated marine ones, the whole belongs to one 

 great aspect of nature. 



It will be found that there can be no exception made to placing 

 the Woolwich and Reading series out of the formation which includes 

 the white chalk; but the propriety on any grounds of linking the 

 Purbecks on to the marine Portland is open to exception. 



Except in instances similar to those of the Carboniferous and 

 Inferior Oolite, and where there is also decided unconformity, the 

 question can only be answered after a careful consideration of the 

 amount and extent of area implicated in the changes in the physical 

 geography which may fairly be assumed to have occurred since the 

 underlying marine deposit was completed. The upheaval of limited 

 marine deposits recognizable as belonging to a particular formation, 

 and the accumulation upon them of freshwater deposits and conglo- 

 merates, would hardly necessitate the belief in such a change in the 

 aspect of nature as would warrant their classification under two 

 great geological ages. But when the same phenomenon is witnessed 

 over widely separated areas, and a conglomerate is followed by some 

 thousands of feet of nuviatile and other freshwater strata (the 

 wreckage of high land close at hand), it becomes certain that the 

 physical change has been wide enough to admit of an alteration in 

 the geological nomenclature. 



"With regard to Sind, the Lower Manchhars usually rest conform- 

 ably on the Gaj marine Miocene, and marine, estuarine, and fresh- 

 water intercalations exist at their base and before the conglomerate 

 is fully developed. In one locality the Manchhars rest on a greatly 

 denuded surface of Gaj strata. 



Upheaval (slow, irregular, and on a very grand scale) occurred 

 subsequently to the deposition of the Gaj series ; and a marine tract 

 became estuarine, nuviatile, and a region of wearing of high land. 

 Subsequently the enormous subsidence took place, doubtless almost 

 synchronously with the deposit of the thousands of feet of the 

 Manchhars ; and yet the sea never broke in : it was far away. 



The area of change was vast ; and it appears to be unreasonable 

 to associate all these deposits under one geological formation. 



The disassociation of the Manchhar and Gaj series is a necessity ; 

 and the nature of the fauna, so singularly allied to that of Pikermi, 

 necessitates its relegation to the early Pliocene time. 



In following up this subject it must be remembered that the 

 Sivalik strata, the horizon of which is above the Lower Manchhars, 

 have a vast vertical as well as horizontal development, and that 

 osseous remains have been found in them throughout their height. 

 The fauna as a whole has a later facies than that of the Lower 

 Manchhars, and resembles, even in its African element, that of 

 Pikermi. 



On the ground of inferred equivalency with the Upper Manchhars, 

 and of faunal alliance with the assemblage at Pikermi, it must be 

 credited that the Sivalik strata are of Pliocene age. 



