Middle Tertiary {Miocene). 
89 
basin exists at Morrison’s diggings on the Moorabool, near Mere* 
ditli where, in some places, the Miocene deposit forms a “ false 
bottom,” on which rest auriferous gravels of Pliocene age. The 
extent of this basin is not well known, but its outlet to the sea 
was unmistakably about where the township of Meredith now 
stands. The great lignite deposit at Lai Lai is possibly of this 
atrc an d there is no doubt as to the lignites of McKirley’s Creek 
Tarwin in Gippsland being so, because they are overlaid 
by Older Volcanic rocks. (Figs. 3o and 36.) 
Ferruginous beds, containing fossil leaves, occur near Bacchus 
Marsh, and beneath the basalt of the Dargo High Plains. In 
many localities throughout the country are exceedingly hard 
quartzites, which appear to be fine siliceous silt, or possibly 
Bio. 36 . — Section at Scalp Creek, east of Tarwin River, 
infusorial earth, cemented and indurated by siliceous infiltrations. 
They often pass into siliceous conglomerates, containing well- 
rounded quartz pebbles, which occasionally show signs of partial 
blending with the siliceous matrix. Hydrothermal action has been 
suggested as a probable cause in the production of these quartzites, 
and it is readily conceivable that the percolation by heated waters 
or steam, of fine sand and gravel or infusorial earth, would result 
in the development of such rocks as the quartzites referred to. 
Wherever the relative positions have been observed, these 
