BY R. H. CAMBAGE. 441 



Having in view the great difference which often exists between 

 the flora on igneous and sedimentary formations, and which is 

 borne out at Bowral by a comparison of plants on the basaltic 

 and sandstone areas, it was with considerable interest that an 

 examination was made of the syenite hill referred to as The Gib. 

 This was done on the 10th February, 1906, in company with Mr. 

 J. E. Carne, F.G.S., when, contrary to expectations, it was found 

 that much of the flora was similar to that of the sandstone 

 areas around; and while some of that found on the basalt was 

 absent, there was to some extent a mingling of the two floras, 

 and this hill seemed to form a sort of neutral ground for the 

 otherwise exclusive plants. Eucalyptus viminalis and E. regnans 

 (E. fastigata) of the basaltic areas were both found here in com- 

 pany with E. Sieberiana and E. piperita, which are both typical 

 of the sedimentary formation. 



In a paper " On the Geology of Mittagong," Messrs. T. Griffith 

 Taylor and D. Mawson, B.E .,* refer to The Gib as representing 

 the denuded plug of an old volcano. " It consists of syenite 

 allied to Bostonite (Harker, p. 117) consisting chiefly of orthoclase 

 felspar. It covers an area of 450 acres, and is surrounded by 

 tilted sandstone on the northern side, while the east slope is 

 overlaid with later basalts." 



When examined in Februai-y last the whole place was recover- 

 ing from the effects of a severe bush fire, so that the following 

 list of plants cannot be regarded as nearly complete, but will 

 suffice to give a fair estimate of the vegetation. The plants 

 noticed were : — Clematis glycitioides DC., Hibbertia BUlardieri 

 F.v.M., H. volub'dis Andr., Bursaria spinosa Cav., Stellaria pun- 

 ge>is Brong., Pelargonium australe Willd., var. erodioides Benth., 

 Pomaderris apetala Labill., Oxylobium, trilobatum F.v.M. (a typical 

 sedimentary plant), Daviesia ulicina Sm., Hardenbergia mono- 

 phylla Benth., Acacia penninervis Sieb.( Black Wattle), A. decur- 

 rens Willd., Rnbus parvifolius L., Eucalyptus regnans (E. fasti- 

 gata), E. viminalis, E. Sieberiana, E. piperita, E. amygdalina, E. 



* Jouin. and Proc. Roy. Soc. N. S. Wales, 1903, pp.315-317. 

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