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vegetable structure. The mode of formation of these coal 

 deposits was perhaps similar to the present-day swamps on 

 the adjacent Murray back-waters. 



From the evidences available the following order of 

 occurrence may be suggested : — 



(1) Denudation of high land immediately preceding a 

 depression of the local area. 



(2) Depression of the area which permitted swamps to 

 form, into which were carried and retained timber and other 

 organic material, the debris of floods and continental drainage. 



(3) The previous dry land (Pre-Cambrian) now became 

 basins in which newer sediments were deposited ; the more 

 elevated portions remained as islands or dry margins. Into 

 the swamps, within the basins, highly carbonaceous muds 

 were carried by floods; this, together with vegetation brought 

 by flood waters and swamp j)lants which grew in situ, formed 

 a peaty deposit. 



(4) Further subsidence, preceded by local changes, 

 caused deposition of less carbonaceous material with a corre- 

 sponding increase of mineral sediments forming shales. 

 Such subsidence permitted the sea to encroach and finally 

 cover some, if not all, of the swamp land. 



(5) Slight elevation then succeeded, and swamp condi- 

 tions again eventuated, with the formation of thick car- 

 bonaceous shales. 



(6) Another subsidence followed and the sea encroached. 

 A series of fluctuations now occurred, evidenced by greenish 

 sands (which contain sharks' teeth), sandstones, marine fossils 

 in limestones, and clays. Finally the whole area was again 

 elevated to dry land and our present-day conditions came 

 into existence. 



