1884.] R. D. Oldham— Geological Notes. 145 



tions in the drawings. He remembered, . at the meeting when the 

 drawings were shown, there was much difference of opinion as to what 

 several of them were intended to represent. 



3. Rough Notes for the construction of a Chapter on the History of 

 the Earth.— By R. D. Oldham, Esq., A. R. S. M. 



(Abstract.) 

 The anthor commenced by referring to the difficulty geologists met 

 with in correlating the strata in different parts of the earth ; he pointed 

 out that in the majority of cases the evidence of entombed fossils was all 

 that was available, and that this was not sufficiently accurate for the 

 purposes of the physical geologist who required some method by which 

 the absolute contemporaneity of far separated beds could be determined. 

 After reviewing the nature and value of the evidence yielded by marine 

 fauna and terrestrial flora respectively, he indicated that a wide-spread 

 glacial epoch such as has affected the earth during the post-tertiary 

 period would give the needed proof of absolute, where the fossils indi- 

 cated approximate, contemporaneity. 



Passing on to the main subject of the paper, he first of all reviewed 

 the floras of the divisions of the Grondwana series, pointing out that 

 those of the Damudas and Rajmahals were of an extremely heterogene- 

 ous character as judged by European standards, and shewed no definite 

 relationship to that of any one European horizon, but that the flora of 

 the Kach beds, which is certainly newer than these, shews a very definite 

 and well-marked relationship with that of the lower oolite. 



In Australia there is a plant-bearing series marked at its base by 

 association with a carboniferous marine fauna and at its upper limit by 

 the presence of Jurassic shells. The Newcastle beds contain a flora 

 allied to that of the Damuelas, above them come the Havvksbury and 

 Uranamatta beds, the latter contains a limited flora allied to the Damudas, 

 while in the overlying beds the only relationship with any Indian flora is 

 a single species allied to a Rajmahal form. In these Hawksbury beds of 

 N. S. Wales and the Bauhus marsh beds of Victoria signs of glacial 

 action have been detected, and the author dwelt on the probability of 

 these having been deposited during the same glacial period as the Indian 

 Talchirs. 



In South Africa he pointed out that at the base of the Karoo beds 

 there was a glacial boulder clay like that of the Talchirs but more 

 strongly developed ; this boulder clay is overlaid by beds which have 

 yielded a limited flora closely allied to that of the Damudas, and 

 these again are overlaid by other beds containing a flora related to that 

 of the Rajmahals. 



