248 Transactions. 



are concerned, the percentage of the Hampden species gradually decreases 

 from the Wharekuri to the Recent. On the other hand, the percentage 

 of the Target Gully and of the Awamoa species gradually decreases from the 

 Wharekuri to the Recent. However, these beds are more closely related 

 to the Otiake beds below them than to the Wanganui beds above them. 

 This obviously points to the probability or certainty that there are 

 intervening beds of an intermediate age which will show a complete faunal 

 gradation. In fact, the uj^per and lower strata in the Wanganui district 

 are very different in age, as is clearly shown by the fact that the 

 higher beds at Castlecliff contain about 90 per cent, of Recent species, 

 while the beds at Waipipi, near Waverley, contain little more than 

 65 per cent. This, however, is a matter that will be worked out more 

 fully subsequently. 



The Bortonian, Trelissick, and Pakaurangi faunas are also tabulated in 

 order that they may be more definitely ^compared with that of the beds 

 near Oamaru. The Bortonian is clearly seen to approach most nearly to 

 the Wharekuri strata, and this fact in itself shows (juite clearly that the 

 basal beds at Borton's are much younger than the basal beds in the Shag 

 Point - Hampden portion of the Oamaru basin. 



The Trelissick formations do not enter so. readily into a comparison 

 with the strata near Oamaru. The character of the fauna is somewhat 

 different, as is clearly shown by the fact that there is a high percentage 

 of lamellibranchs in it. At the same time the upper bed shows a closer 

 approach to the Otiake stratum than to any other in the Oamaru district. 

 This is significant, for the lower Trelissick bed is the middle of the lime- 

 stone horizon in the Canterbury area, while the Otiake bed has the same 

 position in the local series of Oamaru. The upper Trelissick bed, which 

 rests directly on the surface of the limestone, is shown by the table to be 

 much more closely related to the fauna of the Target Gully beds, which 

 also have the corresponding position with reference to the Oamaru lime- 

 stone that the Trelissick (2J beds have to the limestone (Amuri limestone) 

 in that locality. 



The fauna of the Pakaurangi beds is also shown to be more closely 

 related to that of the Target Gully beds than to any other beds of the local 

 Oamaru area, though there is a fairly close affinity with the fauna of 

 Otiake — the Oamaru limestone horizon. This again agrees closely with the 

 stratigraphical position that I have assigned to them. As stated elsewhere, 

 the Pakaurangi beds, in my opinion, rest conformably on the hydraulic 

 limestone, which I have correlated with the Oamaru limestone* (Otiake 

 beds), and are therefore the local equivalent of the Target Gully beds. In 

 applying the table to this matter it must be realized that only 53 per cent, 

 of the Target Gully fauna could occur in the Pakaurangi beds, as is shown 

 by the actual numbers of the species that have been collected. On the 

 other hand, 100 per cent, of the Otiake fossils could occur in it. 



The considerations that have been stated in this paper seem to me to 

 justify the proposal to use the palaeontology of the strata near Oamaru 

 as a basis for the correlation of the Oamaru system of rocks, and I would 



♦Thomson (Trans. X.Z. In.sL, vol. 4S, p. 49, lOKi) objects to the correlation of 

 the hydraulic limestone of North Auckland with the Amuri limestone. It is a fact, 

 however, that the hydraulic limestone rests on strata which contains a Senonian fauna 

 and is covered by "strata which contains a Tertiary fauna - the criterion gi\ en by 

 Thomson for the stratigraphical position of the Amuri limestone. 



