Fox. — The Waitemata Series. 467 



plates and descriptions in Zittel and Stolickza's " Orakei Bay 

 Fossils, " : Waters's papers on " Australian JBryozoa,"! and 

 Tenison- Woods's " New Zealand Corals and Bryozoa."} No 

 attempt was made to identify numerous indistinct remains. 



(b.) There is no volcanic bed between the Parnell grit and 

 the Orakei greensand. The evidence for this will be given 

 when the Parnell grit is described, j It may also be noted 

 that if the Cheltenham breccia were between the two it must 

 have been erupted at Orakei since the greensand was, or else 

 it must appear in section between the two, but nearer the 

 Parnell grit, at the Orakei Stream. || It does neither. The 

 breccia therefore underlies the Orakei greensand. 



(c.) The Orakei greensand is the stratigraphical equivalent 

 of the upper greensands of Turanga. The evidence for this 

 is given better later, and it will be sufficient here to say that 

 the Parnell grit slightly overlies both. Mr. Park found 

 numerous fossils in both, which he compares.^ 



I have slightly rearranged Mr. Park's list. A difficulty, 

 however, confronts us in supposing the Cheltenham breccia 

 and Papakura limestone equivalent beds. How is it that the 

 Parnell grit, a thinner bed, extends to the Turanga greensands 

 and the limestone, while the Cheltenham breccia, a thicker 

 bed, does not ? If it were certain that the former came from 

 Coromandel and the latter from Waitakerei a sufficient reason 

 is given in that their origins lay in opposite directions. But 

 this is not certain, and I am inclined to offer a different ex- 

 planation. It will be noticed that round the Waitemata, in 

 early Oligocene times, sandstones and volcanic beds were laid 

 down, while round Papakura limestones and greensands were 

 deposited ; so that the two areas have different types of sedi- 

 mentation, and must have been laid down under different 

 conditions. When, however, we come to Lower Miocene 

 times the same type prevails over both areas, and when a 

 volcanic bed is deposited, as in the case of the Parnell grit, it 

 is deposited over limestones and sandstones alike. In other 

 words, the conditions of deposit had become the same in both 

 areas. This points apparently to a separation, in the earlier 

 period, of the two areas, probably by a land mass; and there 

 is some independent evidence for this. At Mount Wellington, 

 a basalt puy, the Kev. Percy Smallfield found fragments of 

 Maitai slate which had been erupted by the puy ; so that 

 the slates are probably at no great depth in this locality. 



* " Voyage of ' Novara,' " vol. ii. 



t Q.J.G.S., 1885, &c. 



I Part iv. of the " Palaeontology of New Zealand." 



§ See page 485. 



|| See page 482. 



^1 Geological Eeports. 



