344 Albert V. James : 



beds which coiitain no basalt. Tliese deposits have been dropped 

 by tlie stream as it deepened its bed, but yet the fact should be 

 noted that the great mass of this conglomerate occurs about 100 feet 

 above the present stream level, i.e., when the stream had sunk its 

 bed a little more than 100 feet below the surface. This shows that 

 at that depth the stream cut into an old Kainozoic pebble deposit 

 to tho north, and distributed the pebbles on the convex bank of its 

 meanders. The pebbles lower than 100 feet have probably been, 

 derived partly fiom the old pebble beds, and pa,rtly from the recent 

 deposits higher up the spurs. 



Kiver alluvium, as already described under Physiography, is- 

 poorly represented in this area. It is found chiefly on the down- 

 valley side of the spurs, and it usually passes into and overlies a- 

 heavy river conglomerate. Ihe best deposit is found on Jackson's, 

 Creek, near its junction with Deep Creek. 



Newer Basalt. 



Newer basalt covei's more than nine-tenths of the area maiDped.. 

 It appears to consist of about seven Hows that havei come from Red 

 Hill, Sunbury Hill and Bald Hill. This is sliown by the contour 

 lines on tlie military map, by the dominating position of these vol- 

 canoes, and by the sliape and direction of the vesicles in the basalt.. 

 The points of origin of the earlier flows have not been determined. 

 In many places the basalt has a depth of over 300 ft., but it cannot 

 be said from this that each flow is 43 ft. in thickness, for the earlieir 

 flows are by far the deepest, since they levelled the old denuded 

 surface. In tlie neighbourhood of Column Gully excellent col- 

 umnar structure has been produced in the earlier flows. A de- 

 scription of these columns (14) and the factors producing them (18) 

 may be found in other puUications. 



Upper and Lower Series. — The various flows of newer basalt in 

 this area are divided into Upper and Lower Series by sandstone, 

 bands, river conglomerates, or thick surface soil. • The places where 

 a good junction of the Upper and Lovrer Series can be seen is 

 marked F on the map. Tliat a considerable time interval elapsed 

 between the two series is shown by the denuded surface of the 

 Lower, by its older appearance aiid more decomposed state, and 

 by the thickness of surface soil on the Lower Series. Generally the 

 tliick scree on the valley sides masks the division line of the tAvo 

 series, but excellent junctions are common, especially in the N.\\^. 

 of the area. 



