220 NOTES ON NATIVE FLORA OF NEW SOUTH WALES, IIL, 



fall as the lower countr}^ is reached. But in this lower area, 

 which approximates 1000 feet above sea-level, the further changes 

 in the flora are due to different geological formations, or to the 

 difference between rocky and alluvial situations; and it is worthy 

 of note that among the plants found on the sandstone areas a 

 considerable number belong to coastal genera, and some are 

 actually the same species as those growing on the sandstone 

 around Sydney. It is interesting, therefore, to trace the con- 

 necting links with a view to explaining the distribution of these 

 species. Certain plants are found growing on the Triassic 

 Sandstone near Sydney, many of which continue westwards on 

 to the Blue Mountains, where the geological formation is exactly 

 the same, though owing to the increased elevation, which often 

 exceeds 3000 feet, a considerable number do not reach the 

 mountain tops. Amongst those which do, however, and which 

 therefore are more amenable to geological formation than to 

 climate, several continue over the mountains, and are now found 

 using the various remnants of the once larger sandstone areas as 

 stepping stones till they are carried right out into the western 

 districts amidst surroundings very different from that of their 

 coastal habitat. It is well known that an area of Triassic and 

 Permo-Carboniferous rocks, which under similar conditions pro- 

 duce a somewhat similar vegetation, extends north-westerly 

 towards Gulgong and Dubbo (as well as northwards towards 

 Gunnedah and Narrabri), and it is chiefly along this tract of 

 country that those plants, which to a great extent disregard 

 climatic conditions, have found their way from the coast to this 

 part of the interior or vice versa. 



A careful examination of the flora along this route would 

 reveal many points of interest, not only to the botanist, but also 

 to the geologist who gives any attention to the relation which 

 exists between the vegetation and the geological formation upon 

 which it grows. And in studying the two subjects together 

 some information might be found which would help to decide 

 from which direction certain forms of plant life came, and tho 

 conditions which assisted their distribution. 



