Physiography of Bulla Area. 343 



favour of their lacusti-ine origin. There is no evidence as to 

 whether these sands are pre-older-basaltic or post-older-basaltic'; 

 The examination of the eucalypt leaves by Mr. R. Patton threw no 

 light on the problem of (heir age. Fnmi their position among the 

 other sandy layers, with wliicli they are conformable, it is probable 

 that they are post-older-basaltic, like the normal Kainozoic grits. 



The beds have a decided tilt to the S.E. Ihis may be due to the 

 compression of the loose porous sands by the great overload of new- 

 basalt, which here is about 140 ft. in thickness. 



(d) I're-newer basaltic river sedi/nrnts. — These are shovrn on 

 the map (Plate XXXII.), as areas where plant stems are very 

 abundant. That they are river deposits is shown by their lenticular 

 shape, by the small conglomerate that rests on the valley floor, and 

 by the earthy nature of the matrix. They indicate the sites of 

 pre-newer basaltic valleys. 



(e) Inter-newer basaltic grits and con r/lome rates. — The lava 

 flows of the newer basalt in this district are divided into two 

 series — Upper and Lower. This will be explained later. Between 

 the two series is the old soil surface of weathered rock, and in 

 places tliick deposits of grit have gravitated from the higher grano- 

 ■diorite in the locality into the valleys corroded in the LoAver Series 

 of the newer basalt. These grits, etc., are not stratified. They act 

 as a simple division between the two series of newer basalt. The 

 best occurrences are at points marked F on the map. At Column 

 Gully a heavy conglomerate of quartz and basalt pebbles separates 

 the two series, while in the ]-oad cutting north of Bulla an old land 

 surface separates them. 



(f) Post-newer basaltic grits, conglomerate and alliiviinn. — All 

 these should Ije placed as Recent, but as they form only a later stage 

 in the same destructive and constructive process that has l>een going 

 ■on right through the Kainozoic, they have l>een placed under this 

 head. In the neighbourhood of the heart-shaped granodiorite out- 

 »crop, unstratified grits can be seen both above and l^elow the newer 



basalt. The grits' have been shed from the hill. This process went 

 on before tlie older basalt, before the newer, basalt, and it is being 

 continued after it. Grit covers or mixes with the basalt soil. 



In addition to the massive conglomerates that are now being 

 formed in the stream beds, there are conglomerates of much earlier 

 age formed along the river spurs, especially those of Jackson's 

 Creek, where the deposits are sometimes at least -30 feet in thick- 

 ness. Generally, they are chiefly rounded quartz and l)asalt pebbles, 

 and can thus be distinguished from the normal Kaiudzoic pel.ble 



