454 E. C. ANDREWS. 



Tertiary time consisted of a slightly roughened surface not 

 raised much above sea level. 



It is astonishing that neither Murray nor Baron von 

 Mueller, nor even Sir Frederick McCoy perceived this- 



the mountains from which these streams arose were much 



This statement of Murray brings us t<> the physiographic 

 sitriii , 'iL'ire of the "leads." In each case their channels 

 may be seen to have been excavated rapidly in a peneplain 

 surface. This is evident from the nature of the surround- 

 ing topography, [seeing that the leads, as stated also by 

 Murray, occur on the summits of the highlands] and from 

 the nature both of the channels and the coarseness of the 

 "gutter" wash. It has also been stated by Murray and 

 others that these lead channels in irked a long period of 

 deposition extending in some cases from .Miocene to Upper 

 Pliocene. This is dillicult to understand. Such channels 

 as are occupied by the leads under consideration are of 



for any but the briefest geological or geographical division 

 of time if exposed to the full force of erosive activities 

 such as occurs along any steep channels. These points, 

 however, will receive fuller discussion later. 



The fact that these " leads" and these basalts have been 



" (4,700 ft.) is t 



Physical Geology, 



