139 



Basin. The widely expanded base, relatively small size, and 

 the short stout fang are distinguishing characters. 



Odontas'pis attenuata, Davis, sp. — Two imperfect examples 

 are referred to the above species. It was recorded from the 

 Oamaru Series of New Zealand. In Victoria it is found in 

 the Miocene, and is of the same age in South Australia 

 (Aldingan Series). It also occurs in the Lower Pliocene 

 (Kalimnan) at Beaumaris, Port Philip. 



Section B. 



LIGHT-GREY AND DARK-GREY CLAYS. 



These underlie the greenish and yellowish beds of the 

 previous section. Faint bluish and chocolate colours some- 

 times appear. Sandy beds are not uncommon. These beds 

 are fairly rich in calcium carbonate. Pyrites may enter in 

 noticeable quantity at the base of this section. The pre- 

 dominating dark colour is due to carbonaceous matter, and 

 is doubtless derived from beds of the underlying lignite where 

 exposed in other areas undergoing erosion at the time of 

 deposition of these clays. 



Apart from the colouration due to carbonaceous matter, 

 the beds of this sectioii are very similar to the previous, and 

 appear to be merely a continuation downwards of the same 

 general type of sedimentation. Small marine fossils, prin- 

 cipally gasteropods, are sparsely distributed in this section. 



Section C . 



MARINE LIMESTONE AND CARBONACEOUS MUDS, USUALLY 



PYRITISED. 



This section immediately overlies the lignite series. It 

 is never very thick. A hard dark-grey or, less frequently, 

 light-yellow sandy limestone, full of marine fossil remains, 

 usually limits it above and rests upon a dark sandy mud full 

 of molluscan and other remains. Both the limestone and the 

 mud are usually highly pyritised. At its base it often shows 

 . distinct brecciation, including fragments of slate. So that 

 in all probability there was in progress in the vicinity, at the 

 time of the accumulation of this bed, a great deal of erosion. 

 The black carbonaceous and pyritous condition of the sedi- 

 ments points to material worn down from the previously 

 formed lignitic bed. 



It is without doubt equivalent to Tate's horizons (6) in 

 the Croydon Bore at 1,376 ft. ('"Bituminous clay and black 

 sand; TurriteJJa aldingae" ) ^ and 1,681 ft. (''Bituminous shale; 



(6) Trans. Roy. Soc. S. Austr., vol. xxii.. 1898, p. 195.- 



