154 E. C. ANDREWS. 



sea level and dotted over with residuals, never exceeding 

 1,700 feet in height, extending across the area. From the 

 coast to the inland plains three distinct climates now exist 

 where there was previously only one. This revolution in 

 the climate appears to be no older than the early or late 

 Pliocene, thus many peculiarities of the fauna and flora are 

 due to influences having no greater an extension in time 

 than that of Pliocene or Post Pliocene. Previous to the 

 last complex movement of uplift, the history of the area was 

 one of long continued stable equilibrium near sea level. 

 Economic Significance. 

 Communication. — The model illustrates well the diffi- 

 culties encountered by the pioneers in attempting to reach 

 New England. It must be remembered also that this 

 country of ravines bordering the plateau on the east is clad 

 in dense jungle growths, which contain little or no edible 

 vegetation. 



The reason for the disposition of the main roads and 

 railways is also shown. The position of the Main Northern 

 Railway is seen to be not nearly so dangerous from a 

 military point of view as some imagine, as it is protected 

 by the wild and rugged plateau falls. 



Settlement, Eastern Side. — In this plexus of gorges there 

 is no hope of settling many people, because each family 

 would need from 5,000 to 7,000 acres for comfortable sup- 

 port. On the other hand, relatively small areas of densely 

 watered basaltic and other areas such as those of the 

 Tweed and the Richmond, and the lower valleys of the 

 Clarence, Bellinger, Macleay, Manning and other streams 

 are excellently adapted for purposes of close settlement. 



Plateau. — A large portion of the plateau is of poor nature 

 and not adapted for purposes of close settlement. Excep- 

 tions, however, are the basaltic areas of Dorrigo, Guy 

 Fawkes, Glen Innes-Inverell and the Guyra-Ben Lomond 



