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Correlation by the Genus Pelicaria
Six species of Pelicaria have been recognised from Waitotaran and Nukumaruan beds in East Wairarapa; P. acuminata (Marw.), P. media (Marw.), and P. rotunda n.sp. have a wide geographic distribution; P. rugosa (Marw.) is known from two localities, both south of Martinborough; P. mangaoparia n.sp. is definitely known only from the Mangaopari Stream, and P. convexa (Marw.) from a restricted marine facies of uppermost Nukumaruan or perhaps Castlecliffian age near the junction of the Ruakokopatuna and Makara Streams. Some fragmentary specimens in the Waitotaran in the Taueru Valley may be referable to P. mangaoparia.
The known geographic and stratigraphic ranges of the several species is shown on the stratigraphic columns, figs, 1a and 1b, and they are also summarised in the table Fig. 2.
Five stratigraphic zones can be distinguished in the Mangaopari-Makara area, but only two in the rocks to the north-east, probably in all cases because the facies was unsuited to the existence of the other forms during the period they represent. There is no evidence of any considerable stratigraphic break in the north-
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east. The table (Fig. 2) shows that Pelicaria acuminata is restricted in occurrence to an area from the Manga-o-pari to the Te Ahitaitai Stream, and an area on top of the Mangauraki Range near the Gladstone-East Coast Road. P. rotunda occurs more or less universally in the Waitotaran, but in the Nukumaruan is restricted to the areas immediately east of the Whangaehu River and north of the Ngarara Stream. Apparently Pelicaria acuminata preferred a shallower environment, since it occurs in a rather coarser facies than Pelicaria rotunda and is distributed more or less around the edges of the main basin of deposition. The geographic and stratigraphic relations of the two species are discussed in the section on systematics.
Fig. 2.—Table showing the known distribution of Pelicaria in South East Wairarapa.
Since P. rugosa and P. mangaoparia have not been found in the Whakarua area the downward limit of P. rotunda there is not definitely established. The lowest occurrence known is 500 feet below the top of the Waitotaran, which reaches in all something over 1000 feet. In the Mangaopari Stream one specimen has been collected from loc. V.301, high in the P. mangaoparia zone, but none lower.
The zones distinguished are tabulated as follows:—
| Stages | Zones | |
| Mangaopari area | Whakarua etc. | |
| Upper Nukumaruan | P. convexa | |
| P. media | P. media | |
| Lower Nukumaruan | P. acuminata | |
| P. rugosa | P. rotunda | |
| High Waitotaran | P. mangaoparia |
The beds included in these zones are shown on each of the stratigraphic columns 1—4 figs. 1a, 1b.
The occurrences of other fossils in these rocks have not yet been sufficiently analysed to cite with confidence additional index forms for each zone, but the
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following remarks summarise what is known of the range of the most important of them.
Chlamys delicatulus (Hutt.): At the junction of the Ruakokopatuna and Makara Streams specimens have been found at the top of P. media zone, but to the north it has been found no higher than the middle part of this zone. In the Mangaopari Stream it appears first at the same horizon as P. rugosa. In the north it appears first at about the base of the Nukumaruan, but in the Ngarara-Whakarua area it may have been absent in the Upper Waitotaran owing to unfavourable ecological conditions.
Austrofusus cottoni King: So far this species has been collected only from the P. media zone.
Austrofusus aff. chathamensis Finlay: Known from the P. media zone in the Ngarara Stream and also in the Makahakaha Stream.
Aeneator imperator King: Appears to be confined to the P. rugosa and P. acuminata zones.
Zephos onokeana King: This species occurs in the zone of P. rugosa in the Mangaopari Stream, between localities V303 and V305, the latter being probably basal Nukumaruan. It occurs with P. aff. acuminata in mudstones on the Taueru Road a little west of the Taueru Hotel, the rocks here being near the Waitotaran-Nukumaruan boundary. McBeath has collected it with Z. tuturewa Fleming in the Waitotaran mudstones immediately underlying the Lower Nukumaruan shell limestone (Maungaraki Fmtn.) on the Gladstone East Coast Road. I have not yet had the opportunity to collect from the cliffs east of Lake Ferry, the type locality of Z. onokeana. The list of L. C. King (1933, p. 337) suggests that he has lumped together faunas from some thickness of rocks, representing both the Waitotaran and the Nukumaruan stages. I believe Z. onokeana ranges from the uppermost Waitotaran to the lowermost Nukumaruan and it may be used as a rough index form for the P. rugosa zone.
Aoteadrillia: This genus is represented by several species which are not yet adequately defined. A. beta (King) and A. alpha (King) seem to be confined to the P. mangaoparia and P. rugosa zones. Above this I think they are replaced by A. gamma (King). The ranges of these might be better established after a zonal collection of the type locality (the cliffs east of Lake Ferry). A. trifida Powell, A. bisecta Powell and A. gamma are probably all restricted to the Lower Nukumaruan. In the Upper Nukumaruan (P. media zone) there are many varieties, but all apparently allied to A. wanganuiensis (Hutt) and A. chordata (Suter).