57 



and frequently contains the entire, though much compressed, 

 trunks and branches of trees. The woods are evidently a 

 lignified form of those preserved in a carbonate of lime at 

 Corra Lynn. One tree is very remarkably preserved, the 

 concentric rings and medullary rays with the tissue, are most 

 curiously twisted and contorted by compression. Notwith- 

 standing this, the large porous vessels, and the thick medullary 

 bundles are distinctly visible. The tissue of the pines is 

 scarcely visible in most of those which I have examined.* 



The descending order of the beds at the Big Cutting is as 

 follows : — 



Thickness in feet. 

 Superficial chocolate soil 2 to 3 



Basalt, more or less consolidated and columnar ; 

 with tuffs more or less regularly stratified by 

 water action 50 to 60 



Conglomerate, composed of waterworn rounded 

 fragments of the overlying basalt, mixed with 

 waterworn siliceous pebbles 3 to 4 



Series of whitish arenacious clays 20 to 30 



Lignite more or less impure, with embedded trunks 

 and branches of pine, and other trees with large 

 porous vessels 3 



White and greyish arenacious clays — of great though 

 unknown depth. 



The lignite is thus shown to have been deposited long prior 

 to the more recent volcanic eruptions, and therefore belongs 

 to the Lower Zone, as defined by me in my former paper. The 

 beds of clay and sand of the Lower Zone, so far as I can see, 

 preserve a characteristic white or greyish appearance through- 

 out the group. They are of great thickness and extent, and 

 the section cutting through the Big Hill, may be taken as a 

 fair example of the formation of the many curiously rounded 

 hills throughout this very beautiful district. 



The metamorphosed claystone at Hunter's Mill, Perth, 

 Corra Lynn, St. Leonards, most probably belong to the group, 

 and if so, the Lower Zone (upper and lower boundary) may be 

 indicatedby having its lower members resting upon, and possibly 

 altered by contact with the older basalts, while its upper 

 members are immediately overspread by the more recent. 



It is probable from its height, position, and other circum- 

 stances, that Cocked Hat Hill has been the central vent of 

 the more recent eruption, in this neighbourhood. Its appear- 



* I have since been successful In obtaining sections which show the pine structure 

 admirably. Although the lignites for the most part are composed of the remains of 

 pine trees, yet the intercalated leaf-beds indicate the existence of a rich and varied 

 vegetation of another class. (See figs. 14 and 15.) 



