BY R. II. CAMBAGE. 323 



extension was intersected near the head of Mowitt's Swamp 

 Creek opposite tlie Brogoand Tuross Rivers, where the formation 

 is sedimentary, that forming the actual summit of the Main 

 Eange being a sandy conglomerate, suggestive of the Devonian 

 period, though no fossils were found. The flora of these Iiighly 

 siliceous conglomerate hills differs considerably from that of the 

 granite, the former producing many Sydne}^ and Blue Mountain 

 plants, though often in a dwarfed form owing to the rigid 

 climatic conditions and poorness of soil. The range in this 

 locality has a wonderful effect upon the vegetation. It rises 

 from the west with a fairly pronounced slope, while its eastern 

 face is steep, and scored into deep gullies, as a result of the 

 denudation which is necessarily consequent upon the rapid course 

 of the coastal streams, which, starting at an elevation of about 

 4000 feet, are less than 35 miles from the ocean in a direct line. 

 Having one steep face exposed to the ocean, with the attendant 

 conditions of warmth, shelter, and moisture, as well as being 

 shut off from the drying westerly influence, while the other face 

 has the conditions reversed, this high range exerts a most 

 interesting and decided effect upon the plant-life in this locality. 

 Generally throughout its course the Main Range in New South 

 Wales occupies a position approximating the centre of the moun- 

 tain-area, but ill the vicinity under discussion it forms the 

 eastern margin of the plateau. On ascending from the western 

 side, amongst trees which favour a western aspect, it is noticed 

 as the summit is approached that many of the Eucalypts become 

 dwarfed, though partly owing to the change of geological forma- 

 tion, and after being reduced to some 5-10 feet high, cease 

 altogethe!', the actual crest, for a width of a few hundred j-ards, 

 being nothing more than a heath, with Gasuariiia nana as one 

 of the principal constituents. The evidence of failure, on the 

 part of many western-loving plants, to overcome the warmer 

 coastal influence is most pronounced. Perhaps one of the best 

 examples of failure is to be found in the Snow Gum, Eucalyptus 

 coriacea. Although this tree braves the cold and snowj^ elements 

 better, and ascends higher on our exposed mountains than any 



