CARBONIFEROUS ROCKS OF THE SOUTHERN HEMISPHERE. 271 



may be tentatively referred to the Lochinvar Glacial horizon of New 

 South Wales. R. L. Jack's discoveiy of boulders, about two feet 

 in diameter, near the base of the Middle Bowen formation {op. cit., pp. 

 150-151) does not make it clear whether these supposed ice-rafted 

 boulders occur below the Middle Bowen or are intercalated in them. 

 They are stated to be associated with portions of trunks of coniferous 

 trees, and, as Jack suggests, may have been dropped in heaps from the 

 floating stumps of trees. Probably their horizon is equivalent to that 

 of the Branxton beds of the Upper Marine series of New South "Wales. 



If this correlation is correct the Bowen boulders are on a higher 

 horizon than that of Bacchus Marsh, &c. Certainly at Branxton and 

 West Maitland in New South Wales large boulders, in some cases from 

 one to three tons in weight and occasionally well glaciated, are found 

 on a horizon about six thousand feet above that of the Lochinvar Glacial 

 horizon; and in this thickness of 6,000 feet of strata, chiefly marine, are 

 intercalated the Greta Coal Measures containing in the aggregate from 

 20 to 40 feet of coal. 



Obviously, therefore, in the Lower Hunter area there are two 

 distinct Glacial horizons, the Upper about a third of the way up above 

 the base of the Upper Marine series and the Lower at the very base of 

 the Lower Marine series. With the exception, however, of this case at 

 Branxton and of the Irwin Eiver, and of, perhaps, the Middle Bowen 

 boulders, all the main Permo-Carboniferous horizons in Australia and 

 Tasmania appear to lie at the very base of the Permo-Carboniferous 

 system and can be safely correlated with one another. 



Question 5. In regard to the vast question raised in the Table 

 of Correlation of the Permian, Permo-Carboniferous, and Carboni- 

 ferous Rocks, of the Southern Hemisphere, the following notes are 

 suggested : — 



Under table for New South Wales re ' Rhacopteris-hearing series, ' 

 as Arber now refers Rhacopteris to Aneimites this series might be 

 termed: Aneimiies (Rhacopteris)-heaTmg series. 



I am inclined to the expression Palmo-Permian, not as an exact 

 synonym for Permo-Garhonijerous , but as meaning something older 

 than the Neo-Dyas (Zechstein) horizon, and not only as old as the 

 Paleeo-Dyas (Rothliegendes) but taking in some infra-Rothliegendes 

 rocks which at the same time are newer than the Pennsylvanian of the 

 Upper Carboniferous of North America. 



The term Permo-Carboniferous, on the other hand, while it takes in 

 infra-Rothliegendes rocks should include some rocks which would be 

 considered to be of Upper Carboniferous age. Provisionally it seems 

 to me that we may adopt the following conclusions: — 



(1) That if we may interpret the phenomena of Palaeozoic glacia- 

 tions by those of Pleistocene, the glaciations of the Northern and 

 Southern Hemispheres were so nearly, if not absolutely, synckronous, 

 that they may be referred to the same series of rocks in either hemi- 

 sphere. 



(2) If this be admitted, then the Squantum tillite (admitted by 

 Professor Coleman, W. M. Davis, &c., to be undoubtedly a tillite) 



