BY R. H. CAMBAGE. 687 



them the name of Oak for the Australian trees. The Belah, which 

 has very inconspicuous rays, seems to have kept a distinct name> 

 although it might, through its foliage, easily be confused with 

 other Casuarinas. 



C. Cu7ininghmniana is, so far as I have been able to observe, 

 purely a fresh water tree, and must not be confused with the 

 Swamp Oak, C . glauca, often found near salt water along the 

 coast. The former, in addition to growing near fresh water, is 

 generally an indication of good drinking water, while the latter, 

 though usually on salt flats, will sometimes follow up fresh water 

 creeks, but in such cases it often happens that the stream is 

 sluggish and the water brackish. A remarkable instance of how 

 trees are sometimes restricted to their proper conditions occurs at 

 the head of Burrill Lake near Ulladulla. This inlet is chiefly 

 supplied with ocean water, and in many places on the flats 

 around its margin there are trees of C. glauca (Swamp Oak), 

 which extend westward practically as far as the salt water goes, 

 a distance of about four or five miles. At this point the lake 

 assumes the form of a salt water river, which again narrows at a 

 slightly higher level into a fresh water creek. Oak trees may be 

 seen continuing up the fresh water stream, known as Woodstock 

 Creek, for a distance of scarcely half a mile, but curiously these 

 are not C . glauca at all, but C. Cunninyhamia.na, which with 

 their finer branchlets and smaller fruits can easily be distinguished 

 from the former species. Above the point where the Oaks cease 

 the creek soon becomes smaller, and is scarcely what is considered 

 large enough to boast of Oak trees, while below the River Oaks 

 the water is salt. The nearest point to this at which C. Cunning- 

 ha7niana may be found is on the Clyde River, about a dozen 

 miles westerly across mountains exceeding 1000 feet high. The 

 formation immediately surrounding^ the fresh water Oaks is 

 plutonic, but the country drained by the head waters of the 

 creek is Permo-Carboniferous. It has been suggested to me that 

 possibly these few Oak trees are the surviving descendants of a once 

 more numerous assemblage in prehistoric times. It is believed 

 that there has been an alteration in the relative levels of the land 



