Geography of North- Western Tasmania. 1 83 



conglomerates resting upon Lower Palaeozoic or Archean beds. A 

 straight, well-marked beach line runs across the southern face 

 of the mountain. Its level is quite straight, though it is now 

 tilted slightly from the horizontal, dipping at about 5 degrees to 

 the west. The terrace, so far as could be seen from the steamer, 

 cuts across the bedding of the strata, so that it cannot be due to 

 the outcrop of a band of hard rock. It is clearly a beach line 

 formed when the country stood several hundred feet lower than 

 at present. 



DESCRIPTION OF PLATES. 



1. Sketch map of north-western Tasmania, showing parts of the 



areas occupied by the Central Plateau, and by the 

 North-Western, Henty and Western Pene-Plains ; and 

 the probable former course of the Henby and King 

 Rivers. The Central Plateau is accepted from the map 

 in Johnston's Geology of Tasmania. The Ijoundaries of 

 the pene-plains are approximate, and the limits un- 

 certain. 



2. Sketch of the view across the Henty Pene-Plain from the hill 



face above the Royal Tharsis Mine, Mount Lyell. 



3. Outline sketch across the Henty Pene-plain from the western 



spur of Mount Lyell. 

 Figures 2 and 3 have been drawn by Mr. D. J. Mahoney, from 

 sketches by the author. 



END OF VOL. XVL, PART L 



[Published September, 1903.] 



