BY R. H. CAMBAGE. 639 



with basalt, a basic rock which E. dives always avoids, preferring 

 a sedimentary formation considerably acid, but not necessarily 

 containing a high proportion of free silica. 



In order to flourish in the latitude of Mount Lindsay, this Pep- 

 permint would probably require an altitude of nearly 3,000 feet, 

 and as most of the country between the Liverpool Range and the 

 Nandewar Mountains including part of the Liverpool Plains, is 

 much below that elevation, its occurrence on the latter mountain is 

 difficult to explaui. There is, however, a much denuded range 

 running north-westerly past Currabubula, known as the Peel 

 Range, and connecting the Nandewar Mountains with the Liver- 

 pool Range to the north of Murrurundi, through a gap in which 

 the Namoi River passes near Carroll, and E. dives may possibly 

 have spread from the south along this range, although it is now, 

 for the most part, not sufficiently elevated for the growth of this 

 species. Considering the amount of basic rock, however, on the 

 high land between Coolah or Cassilis and Murrurundi, its passage 

 along this stretch of the Liverpool Range for such a great distance, 

 60-70 miles, on to the Peel Range would be very difficult of ex- 

 planation. At present, there is no record of this species between 

 the Mudgee district and the Nandewars, a distance of about 150 

 miles, and it is difficult to understand how it ever could have 

 occurred continuously under present climatic conditions, without 

 the intervening hills had been formerly mucli higher than now. 



There is the possibility, which seems not unreasonable, that the 

 species may have spread to the Nandewar Mountains towards the 

 close of the glacial period in Pleistocene time, but the evidence in 

 support of this theory is very meagre. At the same time this 

 hypothesis is supported by the fact that there is another southern 

 plant, viz., Asterolasia correifolia, var. Muelleri, in company with 

 this tree, which was hitherto unknown as far north, and the proba- 

 bility of their isolation being due to accidental dispersal by birds 

 becomes, therefore, somewhat discounted. However, E. dives has, 

 by some means, reached the Nandewars, and is sparsely represented 

 on southern New England, but its rarity in the latter locality is 

 possibly largely owing to the fact that much of the geological for- 



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