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Transactions. 



to any appreciable extent the result of recent lateral planation by 

 streams on the resistant underlying rocks, and indicates quite clearly 

 that they are portions of a stripped floor. The dissection of the floor 

 by streams, though not far advanced, obscures the minor tectonic features 

 of the lelief to some extent, for the streams can in no case be consequent 

 on the form of the floor. Theoretically we may expect to find, in addi- 

 tion to insequent, and possibly subsequent, streams, a drainage pattern 

 superposed from the cover, the streams of which, even if wdiolly conse- 

 quent on the form of the cover, may be to a great extent indifferent to 

 minor breaks in the floor. 



The general form of the floor of the Gouland Downs depression may, 

 if we neglect the minor irregularities referred to above, be described as 

 sloping gently in the form of a half-basin from the east, south, and 

 west against the scarp of the Slate Range, which, forms the northern 

 boundary. The lowest part of the basin is at a height of about 2,000 ft. 

 above sea-level. On the western and southern sides the plateau slopes 

 gently up to an even sky-line at a height of about 3.000 ft., beyond 

 which lies the valley system of the Heaphy River. 



The Eastern Boundary. 



Towards the eastern boundary the slope of the surface becomes steeper, 

 as though passing in an anticlinal form, if produced, over Mount Perry 

 and other peaks at the northern end of a range about 4.000 ft. in 



Fig. 8. — View looking north-east aci'oss the Gouland Downs and the " catenary " 



distance in the centre. 



height which bounds the depression on the east. Mount Perry is seen 

 to the left of the centre in Plate IV, fig. 2, and on the right in text 

 fig. 8. In both figures the rise of the plateau surface with increasing 

 steepness towards the range may be noted. The preservation of the 

 surface on slopes of considerable steepness is explained by the fact that 

 the rocks are indurated shale and quartzite, offering great resistance to 

 erosion. Naturally, the stage of dissection of the slopes rapidly ap- 

 proaches maturity as the steepness increases, until, on the flank of the 



