CDc Uictorian naturalist. 



Vol. XXXVII.— No. 10. FEBRUARY 10, 1921. No. 446. 



FIELD NATURALISTS' CLUB OF VICTORIA. 



Owing to traffic restrictions consequent on coal shortage, caused 

 by shipping stoppage, the January meeting of the Club was not 

 held. 



A SKETCH OF THE GEOLOGICAL HISTORY OF AUS- 

 TRALIAN PLANTS : THE CAINOZOIC FLORA. 



By Frederick Chapman, A.L.S., &c.. Palaeontologist to the 

 National Museum, Melbourne. 



(With three plates.) 

 (Read be/ore the Field Naluralisis' Club of Victoria, i^th Dec, 1920.) 

 As already mentioned in a former paper of this series,* evidence 

 has been obtained from the Queensland Mesozoic flora of leaf- 

 remains, which are clearly of dicotyledonous affinities. These 

 remains are as old as the Neocomian stage of the Lower 

 Cretaceous, and they show some relationships to the Waikato 

 Head flora of New Zealand. t Had we no evidence other than 

 that of the fossil flora to show a great time-break between the 

 youngest Austrahan Cretaceous beds and the succeeding 

 Tertiaries, that would alone suffice to emphasize the fact, for 

 the oldest Tertiary or Cainozoic deposits contain quite an 

 advanced type of angiospermous plant-remains. The unfilled 

 gap must be enormous as' regards time, and, as it is incon- 

 ceivable that no deposits were formed during that period, wc 

 are compelled to resort to the idea that subsequent erosion 

 and weathering, in other words pene-planation. is responsililc for' 

 their entire absence from the Australian region. 



Upper Oligocene. — The earhcst definite horizon in the 

 Cainozoic system in which plant remains are found is the Bal- 

 combian. This series can be regarded as equivalent to the 

 Aquitanian (Oligocene of some authors. Lower Mioc(>iH' of 

 others). At Altona Bay and Newport, shafts were sunk some 

 years ago to obtain brown coal. This was obtained at depths 

 of 347 feet II inches in bore 2, parish of Truganina, sec. vii. : 

 at 355 feet 8 inches, at 362 feet 7 inches (scam 2() feet thick), 

 at 393 feet (seam 42 feet thick), at 435 feet (seam 13 feet thick), 

 and at 448 feet (seam 40 feet thick), parish of Truganina, 

 sec. iv., bore No. 3. In the last-named bore a blue clay con- 

 taining shells with a Balcombian aspect, and having a thickness 



* Victorian S'aliiraltst. vol. .\.\xv., No. lo, 1919. p. 15(1. 

 t " Mesozoic Floras of Queensland." parts 3 and 4, (jnecnsiand (luol. 

 Siirv. Ptihl., No. 2C)y 1919, p. 2^,2. 



