332 AUSTRALIAN, SOUTH AFRICAN, AND INDIAN COAL-MEASURES, 



Hector, 1886. I have also used the Fossil Flora of the Coal, &c., 

 by Tenison- Woods, in our Proceedings for 1883 ; Fossil Flora 

 of E. Australia, &c,, by Dr. 0. Feistmantel, Proc. Roy. Soc. N. S. 

 Wales, 1880, p. 103 ; Geology of Tasmania, by Johnston, Hobart, , 

 1888 ; Invertebrate Fauna of the Hawkesbury, (fee, by R. 

 Etheridge, jun., Sydney 1888 ; Capt. F. W. Hutton on the 

 Geology of New Zealand. Q.J.G.S., 1885, p. 191, &c., (fee* 



I take this opportunity of expressing my extreme regret that 

 in discussing Dr.Waagen's paper (Proc. Linn, Soc. ser.ii., Vol. III. 

 p. 1 802). I had omitted to refer to the sources from which it was 

 mainly derived. Dr. Blanford's Montreal Address (B. A. Report 

 for 1884, p. 691). 



In the discussion of the true correlations between the Aus- 

 tralian, South African, and Indian Coal Measures there seems — 

 at least from my point of view — to be betrayed a kind of in- 

 definiteness as to the lines upon which an enquiry which is as 

 much Geographical as Geological should be prosecuted. |^| 



The problem set for solution has now been shown to be not so 

 much purely palseontological as dependent on the reconstruction of 

 ancient climates by the revelation of ancient Geographical con- 

 ditions, such as position, extent and elevation of land surfaces, 

 direction and strength of marine and atmospheric currents, and 

 the alternations of glacial or interglacial periods caused by the 

 varying eccentricities of the earth's orbit, in combination with 

 that rotation of the axis which at long intervals bring the 

 Northern and Southern Hemispheres each in its turn into 

 Summer or Winter perihelion. 



Regarding the princiioles of Dr. Croll's theory as sufficiently 

 established, though unable to follow his developments of those 

 principles with the same degree of acceptation, I cannot conceive 



to 



* I have purposely refrained from quoting from any author not easily 

 accessible in this country, thinking that these Abstracts are sufficient for 

 my purpose. 



