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Volume 51, 1919
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Art. XXIV.—Occurrence of Fossil Moa-bones in the Lower Wanganui Strata.

[Read before the Wanganui Philosophical Society, 7th December, 1819; received by ditor, 30th December, 1918; issued separately, 16th July, 1919.]

Plate XVIII.

No occurrence of fossil remains of the larger species of moa has yet been recorded. Such records as there are of fossil moa-remains were collected by Hutton (Trans. N.Z. Inst., vol. 24, p. 141, 1891). Since the publication of that paper no further record has been made. If it be true, as I have often advocated, that the area of New Zealand has practically been isolated since the Upper Cretaceous period, the development of the numerous species of moa must have taken place within the limits

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of this country. Since there is a great mass of Tertiary rocks in New Zealand, and they are often of a shallow-water origin, it was reasonable to expect that at some time or other remains of the moa would be found in them. It was therefore with some satisfaction that last summer a few bones were discovered embedded in the papa rock forming the cliffs near the Nukumaru Beach. The greater number of the bones were in a poorly preserved condition, but a portion of one femur (Plate XVIII) was in a sufficiently good condition to be identified. It was sent to Professor W. B. Benham, of Otago University, who was good enough to compare it with the large collection of moa-bones in the Otago Museum. My thanks are due to him for the following report on the specimen:—

“The curious trellis of bone lining the medullary cavity is quite similar to what occurs in the long bones of the moas. From our extensive stock of moa-bones I selected for comparison those of Dinornis robustus, and find a very close resemblance to the femur of that species, both in size, details of surface-marking, and thickness of outer wall as seen in transverse section. One small feature that seems characteristic is the small size of the vascular foramen on the posterior face, which is not only relatively smaller in proportion to the size of the femur in this species but absolutely smaller than in other species. Taking this as a starting-point, comparison of the ridges and prominences on this surface agrees quite closely, though not absolutely, with those on D. robustus, where they are more prominent and rather differently formed. This no doubt is explicable by wear and by variation in individuals, or possibly it is specific.

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Femur of Dinornis robutus, showing position of fragment found at Nukumaru.

“I send an outline tracing of the right femur of D. robustus with the fragment shown in position. [See text-figure.] It will be seen, therefore, that the fossil is a portion of the shaft just below the great trochanter…”

“Whether the species is D. robustus or an allied species it would be difficult to decide, but the bird must have been of the same size as that….”

The actual locality where the specimen was found is about three-quarters of a mile south of the Nukumaru Beach. The stratum is composed of a fine pebbly material with much unctuous blue clay. The pebbles are not composed of local material, but seem to be derived from the rocks of north-west Nelson. I have previously drawn attention to the probability of the micaceous sand of Wanganui having its origin in the granite rocks of Nelson. The stratum is regularly interbedded with the other strata of which the cliff is formed, and, like them, it dips south-west 50. A preliminary estimate shows that this stratum lies about 1,000ft. below the highest beds at Castlecliff.

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Some species of Mollusca were found in the bed from which the moa-bones were obtained. These were somewhat rolled, but some of them could be identified. The following is a list of the species that have been identified:—

  • Ancilla novae-zelandiae (Sowerby)

  • Ancilla depressa (Sowerby)

  • Ataxocerithium perplexus Marshall and Murdoch

  • Barnea similis (Gray)

  • Chione crassa Q. and G.

  • Chione stutchburyi (Gray)

  • Cominella maculosa (Martyn)

  • Crepidula gregaria Sowerby

  • Cytherea oblonga (Hanley)

  • Ethalia zelandica (H. & J.)

  • Jucinida levifoliata Marshall and Murdoch

  • Lutraria solida Hutton

  • Mactra discors Gray

  • Mesodesma australe (Gmelin)

  • Mesodesma subtriangulatum (Gray)

  • Ostrea angasi Sowerby

  • Psammobia lineolata Gray

  • Turritella rosea Q. & G.

  • Venericardia zelandica (Deshayes)

  • Venericardia australis Lamarck

This list contains twenty-two species, of which five are extinct. The occurrence of Mesodesma australe confirms the impression of deposition in shallow water made by the pebbly nature of the stratum and by the rolled condition of many of the Mollusca. This species is said by Suter in the Manual of the New Zealand Mollusca to have its habitat between tide-marks.

Another stratum about 40 ft. lower in the series and bearing a larger number of fossils crops out at the beach-level nearly 500 yards farther north. The following species of Mollusca were found in this stratum:—

  • Anachis pisaniopsis (Hutton)

  • Ancilla novae-zelandiae (Sowerby)

  • Ancilla lata Hutton

  • Anomia huttoni Suter

  • Calliostoma hodgei (Hutton)

  • Calliostoma selectum (Chemnitz)

  • Calliostoma ponderosum (Hutton)

  • Calyptraea alta (Hutton)

  • Calyptraea maculata (Q. & G.)

  • Calyptraea scutum Lesson

  • Cantharidus purpuratus (Martyn)

  • Chione spissa (Deshayes)

  • Chione disjecta Perry.

  • Chione stutchburyi (Gray)

  • Cominella virgata A. Ad.

  • Crepidula crepidula Linn.

  • Crepidula gregaria Sowerby

  • Divaricella cumingi (Ad. & Ang.)

  • Dosima subrosea (Gray)

  • Epitonium zelebori (Dunker)

  • Ethalia zelandica (H. & J.)

  • Euthria striata (Hutton)

  • Euthria drewi (Hutton)

  • Fulgoraria arabica (Martyn)

  • Lucinida concinna Hutton

  • Lucinida levifoliata Marshall and Murdoch

  • Lutraria solida Hutton

  • Mangilia protensa (Hutton)

  • Melina zealandiae Suter.

  • Mytilus magellanicus Lamarck

  • Paphia intermedia (Q. & G.)

  • Pecten zelandiae Gray

  • Seila chathamensis Suter

  • Siphonalia subnodosa (Hutton)

  • Struthiolaria frazeri Hutton

  • Trochus tiaratus Q. & G.

  • Trophon ambiguus (Philippi)

  • Trophon cheesemam (Hutton)

  • Turbomlla zealandica (Hutton)

  • Turritella rosea Q. & G.

  • Turritella symmetrica Hutton

An interesting feature of this fossil-bed is the large size of many of the shells: for instance, Lutraria solida, 140 mm. (Hutton's type, 110 mm.); Chione disjecta, 65 mm. (Manual, 58 mm.); Dosima subrosea, 75 mm. (Manual, 48 mm.); Struthiolaria frazeri, 110 mm (Hutton, 75 mm.); Paphia intermedia, 65 mm. (Manual, 57 mm.). Lucimda levifoliata is far larger than other Recent or fossil species of that genus in New Zealand.

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Part of femur of a species of moa found in the lower Wanganui strata near Nukumaru Beach. Natural size.

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It is interesting to have definite evidence that the large species of Dinornis existed when so many extinct species and genera of Mollusca were still living in New Zealand waters.

It is perhaps worth noting that Lutraria solida has not yet been found in any beds on the coast-line higher than that containing the moa-bones. Of other well-known extinct species of Mollusca the following information has now been gained so far as occurrence in the strata on the coast-line is concerned: Melina zelandica, Struthiolaria frazeri, and Crepidula gregaria first occur in the bed that has been mentioned 40 ft. below the moa-bed, and Cardium spatiosum and Ostrea ingens are first found at Wilkie's Bluff, close to the south of the Waitotara mouth. Glycymeris subglobosa first occurs two miles north of the Waitotara. At Mokoia, close to Hawera, a shell of Dosinia magna was obtained.

From the collections that have been made at present it seems that about 90 per cent. of the Mollusca in the Castlecliff beds are of Recent occurrence. In the moa-bed there are about 80 per cent. of Recent species. At the Waipipi Beach, five miles north of the Waitotara mouth, the percentage falls perhaps as low as 65.

I hope to publish a fuller statement of this matter, with lists of the species, next year.