146 R. D. Oldham — Geological Notes. [Sept., 



Having thus obtained a common era for the geological history of 

 these countries, he pointed out that a flora of distinctly Mesozoic facies 

 had lived in Australia in Palaeozoic times, and that at the close of the 

 Palaeozoic or commencement of the secondary epoch it had issued from 

 Australia and spread over what is now the old world, and in this way he 

 explained the existence in the earlier divisions of the Gondwana series 

 of forms of plants which in Europe are only known from beds of much 

 later date. 



Turning then to the question, whether the known facts of the 

 history and distribution of this flora are accountable on the theory that 

 the crust of the earth occupied the same relation towards its axis of 

 rotation as it now does, he pointed out that if we may judge of the 

 severity of the climate by the extent and nature of the glacial deposits 

 of the three countries, the Southern half of Western Australia must 

 then have been in a lower latitude than Central India, and that again 

 than South Africa, and that these conditions are best satisfied by taking 

 the Equator between India and Australia but some 10° nearer the latter, 

 and thence through a point lying between the Cape of Good Hope and 

 the South Pole in about 70° of latitude ; this disposition would bring 

 Central Africa over one of the Poles. 



Reviewing the palaeontological evidence he noticed the arguments 

 for and against the probability of a land connection between India 

 and Africa, and came to the conclusion that such connection pro- 

 bably took the form of a chain of large islands separated by narrow 

 straits, and that the long continued and close relationships between the 

 Indian and African floras pointed to the conclusion that the two regions 

 must have been on the same side of the equator and not on opposite 

 sides as now. 



The paper concluded with a brief review of the arguments which 

 might be urged against this hypothesis on a priori grounds, and pointed 

 out that a rigid nucleus over which the crust of the earth could slide 

 was sufficient to account for the author's requirements. 



Dr. W. King could not but think that many of those present would 

 agree in thanking Mr. Oldham for his original and, on some views per- 

 haps startling, paper. The facts of the palaeontological conditions of the 

 question being such as had for long puzzled geologists in India, a hypo- 

 thesis such as Mr. Oldham had propounded for the solution of these 

 difficulties would be most acceptable if it could be shown to hold good. 

 The view, however, of the movement of the earth's crust in such a way 

 over the central mass was very difficult of conception ; and an objection 

 to it had been offered by a mathematical friend. This was that though 

 it might be conceivable that the crust of the earth should move over the 



