^Qi?'] Hart, Eucalypts about Creswick and Clnnes. 107 



E. sideroxylon, about 1,100 feet, but the occurrence of this 

 species west of Bacchus Marsh would be a little higher. 



The question presents itself whether the low part of the 

 Divide west of Creswick has allowed passage of northern species 

 to the south, or vice versa. The Divide might be an obstacle 

 either on account of its elevation or of the existence of its own 

 type of forest, with which some other species might not be 

 able to compete. However, a considerable part of the Divide 

 between Creswick and the Pyrenees is rather low, and the 

 bedrock ranges east of the Pyrenees, and sheltered by them 

 from the west, would need to be. included in considering this 

 question. These I have not examined. At Creswick the 

 occurences of Yellow Box and of Red Stringybark do not seem 

 to mark their line of migration to the south. Yellow Gum might 

 be expected to follow the junction of the ranges and the 

 plains, and can grow on the plains, but it does not reach to 

 the elevations of the lowest part of the Divide. In the past, 

 with a lower level of the land it might have crossed, but it is 

 far more likely that it has travelled from the west along both 

 flanks of the central ranges. Red Gum is also abundant on 

 lower . country on both sides of the Divide, and might easily 

 have reached the vicinity of the Divide from both sides 

 independently, but it may also cross at places further west, 

 for its highest levels are not far from the Divide. 



On the other hand, the Swamp Gum and White Sallee would 

 be assisted to spread across the Divide by the volcanic strip, 

 not, however, because it is low, but because the competition 

 of other species is removed. The Swamp Gum could spread 

 across by the valleys in the ranges also, and no doubt has done 

 so. For the White Sallee the parts of the Divide with volcanic 

 soils would appear a distinct advantage at these levels, if it 

 is correctly considered to dislike close competition under the 

 conditions here. Near those high levels at which it is the 

 chief or only tree it is evidently in no need of facilities to cross 

 the Divide. 



In conclusion, I would acknowledge my indebtedness to Mr. 

 P. R. H. St. John for many pleasant discussions of points 

 which have arisen and for identification and confirmation of 

 some species. I would also refer to the usefulness of Howitt's 

 paper on the eucalypts of Gippsland. When we read that 

 paper and find that we can follow each species in spite of the 

 fact that what we regard as species were in many cases regarded 

 then as varieties within a species, we recognize the value of the 

 precision and clearness of his observations. A caution may be 

 necessary to look carefully at his use of the term " littoral," 

 clearly defined by him, but not always clear in quotations from 

 his work. 



