(a) Key fauna of Lower Bortonian.
(F) Hormosina cf. globulifera Brady, Cyclammina grangei, *Vulvulina cf. advena Cush., Eggerella decepta, Gaudryina reliqua, *Marginulinopsis marshalli and waiparaensis, *Sigmoidella bortonica, *Buliminella browni, *Elphidium hampdenensis, *Globorotalia crater. G. reliqua and M. waiparaensis are diagnostic of the Lowest Bortonian zone.
First appearance of:—
(Ostracoda.) An assemblage different from that in the Piripauan appears, and lasts with little apparent specific change (but occasional additions) to the Awamoan or later.
(F) *Karreriella Cush. (as novozealandica Cush.), *Marginulinopsis Silv., Langenoglandulina Silv., *Sigmoidella C. and O., Sigmomorphina C. and O., Zeauvigerina, Aragonia (as zelandica), *Rectobolivina Cush. (as bortonica), *Hopkinsina H. and W. (as wanzea), *Angulogerina Cush. (as australis H.-A. and E.), *Trifarina Cush. (as bradyi Cush.), Cassidulina d'Orb. (as subglobosa Brady), *Nonion Mont. (as maoricum Stache), Notorotalia (as tiny species).
*Bolivinopsis cubensis (C. and B.), Textularia zeaggluta, Karrerulina bortonica, *Pseudogaudryina proreussi, Clavulinoides instar, *Dorothia agrestis, Marssonella cf. identata (C. and J.), *Sigmoilina tenuis (Czjzek), *Vaginulina cf. elegans Cush., Zeauvigerina parri, *Bulimina truncanella and pahiensis, *Cerobertina kakahocia, Ellipsoglandulina subconica (Kreuz.), *Ellipsonodosaria globulifera (Kreuz.) (of verneuili line), *Nonion iota, *Nonionella zenitens, Notorotalia aff. alabamensis (C. and McG.), *Pulvinulinella
tenuimarginata C., P., and C., Anomalina visenda and *eosuturalis, *Cibicides parki (rare and small till Upper Bortonian), tholus, and *collinsi, *Discorbis appositus, *Globorotalia collactea.
Last appearance of:—
(F) Karrerulina aegra, Allomorphina trochoides (Reuss).
(b) Key fuana of Upper Bortonian.
(M) *Crassatellites Krug. (s. str.), *Monalaria Marw. (1924B, p. 173), Paryphostoma Bayan, *Fascioplex Marw. (1934, p. 15), Priscoficus Con. (see Fin. and Marw., 1937, p. 75), *Notoplejona Marw. (1926C, p. 270), Marwickara Laws (1935, p. 28), Speightia Fin. (1926B, p. 25).
*Glycimerita subglobosa (Sut.), Lopha gudexi (Sut.), Duplipecten waihaoensis (Sut.), Venericardia acanthodes Sut., *Dosinia mackayi Marw., *Carinacca allani (Marw.), Spirocolpus rudis (Marsh.), Mathilda prima Laws, Galeodea modesta (Sut.), Dicroloma zelandica Marsh., Waimatea amplexa Fin., Waihaoia thomsoni Marw., Mauia biconica (Sut.), and curvispina Marw., Marshallena serotina (Sut.), Insolentia sertula (Sut.), Zemacies torticostata (Marsh.), “Hemifusus” goniodes Sut.
(F) Assilina d'Orb., Discocyclina Gümbel, Asterocyclina Gümbel, Plectina Marss. (as quennelli and agrestior).
Vulvulina cf. colei Cush., Siphotextularia acutangula, Palmula marshalli, Lagena n.sp. aff. orbignyana Seg. (with pustuled centre), Zeauvigerina zelandica, Siphogenerina prisca, Elphidium saginatum, Nuttallides subtrümpyi (large specimens), Discorbis jugosus.
First appearance of:—
(M) Lentipecten Marw., Serripecten Marw., Pleuromeris Say., Spissatella Fin., Senectidens Ired., Gari Schum., *Notocorbula Ired., *Marama Marw., Hina Marw., *Offadesma Ired., ? Risellopsis Kest., *Carinacca Marw., Magnatica Marw., Friginatica Hed., Taniella F. and M., *Spirocolpus Fin., Zeacolpus Fin., Austrosassia Fin., Galeodea Link, *Euspinacassis Fin., *Ficus Roed., Niso Risso, Tioria Marw., Falsicolus Fin., Austrofusus Kob., Poirieria Jouss., Waimatea Fin., Waihaoia Marw., Mauia Marw., *Baryspira Fischer, Marginella Gray, Anapepta Fin., Bonellitia Coss., Zemacies Fin., Marshallena Fin., Borsonia Bell, Zeacuminia Fin., Gemmula Weink., Superstes F. and M.
(M: Cephalopoda) Aturia Bronn.
(F) Frankeina C. and A. as large forms, Arenodosaria (as antipoda Stache), Spiroloculina d'Orb. (as n.sp.) Plectofrondicularia of vaughani Cush. line (as whaingaroica Stache), Astrononion C. and E. (as n.sp.), Cancris Mont. (as compressus), Laticarinina G. and W. (as halophora Stache), Epistomina Terq. (as cf. elegans d'Orb.), Hantkenina Cush. (as australis), Globigerinoides Cush. (as index).
Ammodiscus archimedis (Stache), Vulvulina pennatula (Batsch), Listerella levis, Marginulinopsis hochstetteri (Stache) and spinulosa (Stache), Palmula bivium, Citharinella tenuissima (Hantken), Hopkinsina bortotara, Bulimina forticosta, Rotaliatina sulcigera (Stache), Gyroidina scrobiculata, Anomalina semiteres.
The following have their earliest occurrence in the Eyre River Asterocyclina bed (see Speight, 1928, pp. 413–419), which seems to form the base of the Upper Bortonian, but whose faunal facies is very different from that of any other Bortonian locality, and more like that of the Waiarekan zone of the Kaiatan:—Verneuilina d'Orb. (as aff. novozealandica Cush.), Asterigerina d'Orb. (as n.sp.), Eponides concentricus (P. and J.), Calcarina d'Orb. (as aff. mackayi Karrer), Discorbis of pulvinatus (Brady) line, Heronallenia C. and P. (as wilsoni H.-A. and E.), Vagocibicides (as primitive n.sp.), Planorbulina d'Orb. (as n.sp.).
Last appearance of:—
(M) Electroma Stol., Perissoptera Tate, Pseudofax F. and M.
(F) Recurvoides Earl., Glomospira Rzehak (as corona C. and J.), Zeauvigerina, Aragonia (as zelandica), Nuttallides (as subtrümpyi), Quadrimorphina (in any abundance, allomorphinoides very rare in Kaiatan).
Ammodiscus glabratus C. and J., Trochamminoides irregularis White, Bolivinopsis spectabilis (Gryzb.) and aff. rosula (Ehrenb.), Textularia cf. eocenica Gümbel, Pseudogaudryina proreussi, Dorothia agrestis, Zeauvigerina parri, Rectobolivina bortonica, Hopkinsina wanzea, Bulimina quadrata Plummer, bortonica, and pahiensis, Anomalina visenda, Notorotalia aff. alabamensis C. and McG., Cibicides tholus, Globorotalia collactea.
Type Locality:—McCullough's Bridge, Waihao River, South Canterbury (Allan, 1933, p. 93).
Sediments:—Greensand, 50 ft. thick, outcropping over only a few square chains; rests conformably on Upper Bortonian (by micro-fauna) but is separated by a phosphatic zone. Overlian apparently conformably by glauconitic marl with Duntroonian micro-fauna.
Fauna:—Molluses rich (see Allan, 1926, p. 291); forams well preserved but uncommon and difficult to extract. Dr. C. O. Hutton, of the Geological Survey, has recently successfully removed the glauconite from such samples with an electromagnet.
Correlatives:—Several Tahuian molluses in an old collection of T. Esdaile were labelled as from Waiareka Valley, North Otago (see Marwick, 1926A), but the locality has not been confirmed, and the specimens were probably from McCullough's Bridge. No other Tahuian locality has been recognised by means of molluses. Forams indicate correlation with highest bed of Hampden mudstone, the “Burnside Marl” (very rich), and a Mid-Waipara zone below Amuri Chalk Marls.
(M) *Neverita Risso, *Cordieria Rouault.
*Limopsis waihaoensis Allan, *Carinacca waihaoensis (Sut.), *Eulima waihaoensis Allan, *Waimatea inconspicua (Hutt.), *Waihaoia allani Marw., *Conospirus tahuensis (Allan), *Marshallena formosa (Allan), *Gemmula bimarginata (Sut.), *G. complicata (Sut.), *G. duplex (Sut.), *Parasyrinx finlayi (Allan), *Cordieria rudis (Hutt.), *Zeacuminia sulcata (Hutt.).
(F) Palmula bensoni. This is very rare, and at present no other limited species is known, the chief distinction of the stage being the absence of important forms of underlying and overlying horizons (e.g., Pseudogaudryina proreussi, Gümbelina ototara, Zeauvigerina, Bolivina anastomosa, Bulimina bortonica, Nonion of pompilioides line, Nuttallides, Cibicides pseudoconvexus).
First appearance of:—
(M) Callolima Bartsch, *Tanea Marw., *Spelaenacca Fin., *Eulima Risso, *Coluzea Fin., *Proximitra Fin., *Parvimitra Fin., *Conospirus de Greg., *Parasyrinx Fin.
(B) *Aetheia gualteri (Morris).
(F) *Pseudogaudryna reussi (Stache), *Arenodosaria robusta (Stache), Plectofrondicularia whaingaroica (Stache) striate form, *Bulimina pupula Stache, Eponides umbonatus (Reuss).
Last appearance of:—
(M) *Carinacca Marw.
(F) *Palmula bivium, *Globorotalia cf. dehiscens C., P., and C.
Type Locality:—Kaiata district, Greymouth Subdivision, North Westland (Finlay, 1939A, p. 531; Allan, 1933, p. 91).
Sediments:—Mudstone, 2000–3000 ft. thick, outcropping over many square miles in Westland, resting apparently conformably on the Island Sandstone of Bortonian age (see Henderson, 1929, p. 284). The Tahuian has not been recognised there, and seems absent, the lowest Kaiata Mudstone being apparently still Ototaran in the wide sense. The Kaiatan is overlain conformably by the upper Point Elizabeth beds, of Whaingaroan age.
Fauna:—Molluscs extremely rare (a small *Spirocolpus is the only one of note); forams everywhere abundant.
Correlatives:—(By forams) the Lower Ototaran of Oamaru district (limestone with brachiopods, diatoms, sponge spienles locally abundant), basal tuffaceous part of same, and tuffs of Lorne (type of Waiarekan zone, with distinctive molluses), covering many square miles in North Otago; Omotumotu beds and lower Point Elizabeth beds in the type area. In North Island known only in Elsthorp district of Hawke's Bay, but probably fragments elsewhere.
The molluscan fauna is taken almost entirely from the Waiarekan zone (see Marwick, 1926A, p. 307), all other facies of the Lower Ototaran being poor in macro-fossils.
The micro-faunas plainly indicate a definite two-fold division of the Ototaran, with a few possible zones of lesser importance. The molluses have not shown this before simly because they are generally so rare and poorly preserved in this period. The three or four-fold division on brachiopod faunules suggested by Thomson (1926A, p. 152) and Allan (1933, p. 92) is not confirmed by the Foraminifera, and is in any case impracticable outside the Oamaru coastal area, for the assemblages occur hardly anywhere else separately and nowhere else in sequence. They cannot, for example, be applied to
divide and correlate the great thickness of Ototaran s.l. in Westland (though the various micro-faunas from here exactly correspond with those of the Oamaru formations), thus indicating once again the uncertainty of isolated brachiopod faunules for long-distance correlation.
(M) Danilia Brus. (as neozelanica Laws), Agathirses Mont. (as senex Marw.),
Fossularca januaria Marw., Chlamys venosus (Hutt.), Serripecten enfieldensis (Marw.), Spissatella media (Marw.), Venericardia benhami. Thomson, Argalista proimpervia Laws, Incilaster marshalli (Thomson), Spirocolpus tophinus (Marw.), Semitriton revolutum (Fin.), Erato vulcania Marw.
(B) Liothyrella pulchra Th., Stethothyris uttleyi Th., Terebratella totarensis Th.
(F) Probably *Halkyardia H.-A. and E. (as bartrumi Parr, 1934, p. 144; and undescribed species), and probably Operculina d'Orb. (as kawakawaensis Chap. and Parr).
Bolivina pontis, Siphogenerina postprandia, *Robertina lornensis, *Eponides lornensis, *Asterigerina waiareka and lornensis, *Cibicides pseudoconvexus Parr (common, very rare in Whaingaroan).
First appearance of:—
(M) Grandaxinea Ired., Trichomusculus Ired., Pedalion Huddesf., Ascitellina Marw., Nemocardium Meek (large forms), Emarginula Lamk., Semitriton Cossm., Mayena Ired.
(B) Liothyrella Th. (as boehmi Th., oamarutica Boehm, and pulchra Th.), Stcthothyris Th. (as uttleyi Th., and tapirina Hutt.). Terebratulina suessi (Hutt.).
(F) Wiesnerella Cush. (as n.sp.), *Polymorphina d'Orb. s.str. (as n.sp.), *Reussella Gal. (as n.sp.), *Angulogerina of the rugoplicata Cush. line (except for one record in Upper Bortonian), *Parvicarinina (as altocamerata H.-A. and E.), *Carpenteria Gray (as rotaliformis Chap. and Cresp. and other species).
*Textularia cuspis, *Siphotextularia heterostoma (Forn.), Gaudryina minuscula, *Marginulinopsis asprocostulata (Stache), *Gümbellina ototara, *Bolivina anastomosa, *Buliminella of elegans d'Orb. line, *Patellina corrugata Will., *Nonion of pompilioides F. and M. line, *Astrononion cf. australe C. and E., *Notorotalia large species, *Cibicides perforatus (Karrer) and verrucosus.
Last appearance of:—
(M) None known as yet.
(F) *Asterigerina d'Orb. (as large forms; several species; a rare and tiny undescribed species in Duntroonian and Lower Hutchinsonian), *Hantkenina Cush. (as australis), *Globigerinoides Cush. (as index; genus re-enters in Pliocene).
*Listerella levis, *Karrerulina bortonica, *Plectofrondicularia whaingaroica (Stache) striate form, *Hopkinsina bortotara (rare specimens in Whaingaroan), *Nonion iota, *Gyroidina scrobiculata, *Anomalina semiteres, *Cibicides parki, *Globigerina linaperta.
Type Locality:—Whaingaroa Harbour, Huntly-Kawhia Subdivision (Whaingaroa Beds of Henderson and Grange, 1926, p. 46).
Sediments:—Calcareous mudstone, 100 + ft. thick; rests on coal measures, and these on old basement rocks. Overlain, apparently conformably, by Te Kuiti limestone, of Waitakian age.
Fauna:—Molluses insignificant; forams abundant.
Correlatives:—(By forams entirely.) Many square miles of calcareous claystone in Huntly-Kawhia Subdivision and southward into Te Kuiti Subdivision, forming the basal marine Tertiary and marking a wide transgression. Scattered areas in Poverty Bay of more or less glauconitic sandy marl. Light coloured, fine to sandy marls, Hawke's Bay, Weber Series (ongley, 1935). Upper Ototaran of North Otago, North Canterbury, and Westland, mostly more highly calcareous facies (Kakanui, Oxford, Upper Amuri, and Cobden limestones, etc.), generally resting conformably on Kaiatan beds or intervening tuffs.
This stage more than any other depends on Foraminifera for its palaeontological basis; the Kaiatan mostly does also, but has a zone with a molluscan fauna. Brachiopods are locally abundant in the North Otago correlatives of these stages, but are so discontinuous and sensitive to environment that their practical use in correlation is limited. Too little is known of their ranges in most cases,† and though many are useful in the Oamaru district, the possibility that they are largely paleic indicators must not be overlooked. In thus stating our views we are not disparaging the usefulness of brachiopods; any organism that gives any clue to the age of strata must be considered, and this phylum can be of great local use (perhaps of even zonal value in the Hutchinsonian). But it has obvious limitations in the gregarious nature and sporadic occurrence of its members (see Thomson, 1926A, p. 151) and experience has shown that for correlation throughout the Tertiary much greater reliance has to be placed on the Mollusea and Foraminifera. The absence of particular brachiopod faunules furnishes only “negative evidence,” and should be used very cautiously in correlation and in postulating sequential gaps.
(M) *Janupecten polemicus Marw. and utteyi Marw.
(B) Tegulorhynchia sublaevis Th. and squamosa (Hutt.), Liothyrella gravida (Suess), concentrica (Hutt.), and kakanuiensis (Hutt.), Terebratella radiata Hutt., Terebratulina oamarutica Boehm, Lingula waikatoensis Pens.
(F) *Sigmoilina cf. edwardsi Schl., *Lagena n.sp. aff. orbignyana Seg. (with vertically ribbed centre), *Polymorphina lingulata Stache, *Uvigerina maynei Chap., *Notorotalia stachei, *Globigerina angipora Stache.
[Footnote] † Compare Allan's surprise (1937, p. 150) at the extension of the range of his Rhizothyris labiata, a distinctive post-Hutchinsonian species at Clifden, but Hutchinsonian elsewhere in Southland.
First appearance of:—
(M) Janupecten Marw., Crenostrea Marw., Atamarcia Marw.
(B) Neobouchardia Th. (as minima Th.), Tegulorhynchia depressa Th.
(F) *Technitella Norman (common; very rare in Tahuian), *Flabellamina Cush. as large forms, *Semivulvulina (as capitata Stache), *Bigenerina d'Orb. (as n.sp.), *Haeuslerella Parr (as textilariformis Stache), *Lingulina d'Orb. as large forms of costata d'Orb. line, *Plectofrondicularia Liebus s.str. (as parri; extremely rare till Hutchinsonian), *Bolivinella Cush., *Cassidulinoides Cush., *Pseudononion Asano, *Siphonina Reuss, *Amphistegina d'Orb. (extremely rare in Kaiatan), *Chilostomelloides Cush.
*Dorothia minima (Karrer), Listerella weymouthi, *Verneuilina novozealandica Cush. (= browni Fin.), *Gaudryina cf. quadrangularis Bagg, Liebusella bradyi (Cush.), *Robulus haasti (Stache), *loculosus (Stache), *vortex (F. and M.), and *dicampylus (Franz.), *Marginulina of costata Batsch line, *Vaginulina of legumen line (as oristellata (Stache), *Lagenonodosaria of scalaris (Batsch) and *hirsuta (d'Orb.) lines, *Palmula taranakia, *Bolivina lapsus (not common till Hutchinsonian), *Siphogenerina striatissima (Stache), Bulimina cf. spiniscens Brady and scobinata, Cassidulina cf. oblonga Reuss, *Elphidium ornatissimum (Karrer), *Gyroidina zelandica, Planulina aff. wuellerstorfi (Schw.), *Anomalina vitrinoda, *Cibicides thiara (Stache), *Globorotalia of scitula Brady line.
Last appearance of:—
(M) None known as yet.
(B) Liothyrella oamarutica (Boehm).
(F) *Citharinella Marie (as tenuissima Hantk.), *Gümbelino Egger (as ototara), *Rotaliatina Cush. (as sulcigera Stache).
*Textularia zeaggluta and *cuspis, *Karreriella novozealandica Cush., *Pseudogaudryina reussi (Stache), *Spiroloculina n.sp. of Bortonian, *Marginulinopsis hochstetteri (Stache), *asprocostulata (Stache), and *spinulosa (Stache), Bulimina forticosta, *Cerobertina kakahoica, *Cancris compressus, *Anomalina eosuturalis and eoglabra, Discorbis of pulvinatus (Brady) line and *appositus, Cibicides collinsi.
Type Locality:—North (or left) branch of London Creek, North Otago (Allan, 1938, p. 89).
Sediments:—Glauconitic sandstone, 4 ft. thick, resting conformably on Whaingaroan limestone. Overlain by unfossiliferous nodular limestone apparently similar to the basal Hutchinsonian conglomerate. followed by sandstone with Lower Hutchinsonian brachiopods (Pachymagas hectori Th., etc.).
Fauna:—Brachiopods abundant (see Thompson, 1926A, pp. 152–154); forams a few.
Correlatives:—(By brachiopods.) Lower part of Duntroon and Ngapara limestones (glauconitic), and the Waihao, Cave, Otaio, and Weka Pass limestones and Stavely greensand of Canterbury. Forams
in these locally abundant, enabling correlation with Chatton sands (Southland) and upper Wharekuri greensands (North Otago) (both with molluscs abundant), and with Te Kuiti Limestone (lower part at least) of North Island.
(M) Trigonostoma Blainv.
Neilo sinangula Fin., Glycimerita thomsoni (Marw.), Chlamys compitum (Marw.), Spissatella subobesa (M. and M.), Pyrazus sutherlandi Marw.
(B) *Liothyrella landonensis Th., *“Waiparia” elliptica (Th.), Murravia catinuliformis (Tate), *Rhizothyris undescribed dwarf spp.
(F) Pseudogaudryina anachrons, Lingulina semilineata Chap., Elongobula chattonensis and lawsi, Nonion aff. chapapotensis Cole.
First appearance of:—
(M) Veletuceta Ired., Gigantostrea Sacco, Athlopecten Marw., Lima Brug. (s.str.), Cyclocardia Con., Notomyrtea Ired., Gonimyrtea Marw., Finlayella Laws, Raina Marw., Fossacallista Marw., Bassina J.-B., Eumarcia Ired., Myadora Gray (as small forms), Salaputium Ired., Solecurtus Blainv., Zeminolia Fin., Neojanacus Sut. (Laws, 1935, p. 33), Sinum Roed., Maoricolpus Fin., Notacirsa Fin., Struthiolaria Gray, Pyrazus Mont., Zefallacia Fin., Pareora Marw., Trichosirius Fin., Xymenella Fin., Typhis Mont., Clifdenia Laws, Procominula Fin., Cominista Fin., Baryspira Fisch. (with heavy callus), Alcithoe Sw., Spinomelon Marw., Metamelon Marw., Teremelon Marw., Austrotoma Fin., Comitas Fin., Scaphander Mont., Ringicula Desh.
“Cardium” of spatiosum Hutt. line, Polinices huttoni (v. Iher.), Globisinum crassiliratum Fin.
(B) Pachymagas Th. (as huttoni line), *Rhizothyris Th. (as dwarf species; see Thomson, 1926A, p. 149), *Tegulorhynchia masoni Allan.
(F) Polymorphina d'Orb. very elongate species, Pseudopolymorphina C. and O. (both smooth and striate species), Ceratobulimina Toula (as kellumi).
Matanzia mahoenuia, Karreriella cushmani, Sigmoilina of the arenaceous type (as sp. aff. celata Costa), Lenticulina mamilligera (Karr.), Marginulina allani, Cassidulina pacifica Cush., Ellipsonodosaria verneuili (d'Orb.), Pseudononion stachei (Cush.), Astrononion of novozealandicum C. and E. line, Nonionella magnalingua, Cancris lateralis, Notorotalia serrata, tenuissima (Karr.), and large forms of spinosa (Chap.) line, Eponides cf. broeckhianus (Karr.), Gyroidina allani, Anomalina miosuturalis, subnonionoides, pinguiglabra, and macraglabra, Cibicides novozelandicus (Karr.), catillus, and ihungia, Discorbis turgidus, Globorotalia dehiscens C., P., and C., Globigerina bulloides d'Orb. (typical).
Last appearance of:—
(M) Janupecten Marw., Niso Risso.
(B) *Stethothyris tapirina (Hutt.), *Tegulorhynchia depressa Th.
(F) Pseudogaudryina of reussi line (as anachrons), Marginulinopsis of hochstetteri (Stache) line (as n.spp.), Vaginulina cristellata (Stache), Siphogenerina striatissima (Stache), Cibicides thiara (Stache).
Type Locality:—Waitaki limestone and Otiake beds, Waitaki Valley, North Otago (Allan, 1933, p. 97; Park, 1918, pp. 25, 83).
Sediments:—Arenaceous limestone, 150 + ft. thick, resting on greensands (with Duntroonian micro-fauna, but without the characteristic brachiopods, which are abundant in greensands in the same valley not far away). Overlain by river gravels.
Fauna:—Molluscs abundant (generically like those of Wharekuri and Awamoa, but specifically mostly different from either); brachiopods mainly of Pachymagas huttoni line, but also grading to parki types; forams abundant, but of few species and indicating an uncommon facies.
Correlatives:—(By molluscs and lithology.) A similar limestone across Waitaki River in South Canterbury, and also at Wharekuri, North Otago. Probably calcareous sandy mudstones in Waipawa area, Hawke's Bay, and Huntly-Kawhia area.
(M) *Fossacallista watti Marw., *Dosinula uttleyi Marw., *Waimatea transilis Fin., *“Turris” uttleyi Sut.; many new species as yet unnamed.
(B) *Pachymagas huttoni Th. typical (with allied species verging towards parki series).
(F) ? *Guttulina yabei C. and O., ? *Pseudopolymorphina doanei (G. and W.), Uvigerina dorreeni. These and other forms common in Waitakian may extend down to Duntroonian; even the slight differences recorded here in the faunas may be due, not to time, but to the distinct facies involved, the Duntroonian being mostly much more glauconitic and coarser in sediment. Allan (1938) mentions several lithologies, however, and it will be necessary to collect micro-faunas from each of these for comparison, also systematic collections throughout the type Waitakian.
First appearance of:—
(M) *Divaricella v. Mart., *Uberella Fin., *Proterato Schild. (s.str.), *Eucominia Fin., *Neocola Fin., *Inglisella Fin., *Rugobela Fin., *Cryptomella Fin., *Pervicacia Ired.
(B) *Pachymagas approaching parki series (similar types).
(F) *Semivulvulina waitakia, Plectofrondicularia awamoana (rare till Awamoan), Uvigerina of canariensis d'Orb. line, Siphogenerina ongleyi, Bulimina miolaevis, Cassidulina cuneata, Cibicides mediocris.
Last appearance of:—
(M) *Athlopecten Marw., *Spirocolpus Fin.
(B) *Pachymagas of the huttoni Th. series.
(F) *Polymorphina d'Orb.
*Haeuslerella textilariformis (Stache), Bulimina scobinata, *Gyroidina allani (possibly in Lower Hutchinsonian), Cibicides verrucosus, Marginulina allani.
Type Locality:—Hutchinson's quarry, Oamaru (see Allan, 1933, p. 88).
Sediments:—Greensands, 20 ft. thick, with basal conglomerate; unconformably overlying current-bedded tuffs, limestone, and glauconite, which in turn rest on more tuffaceous sediments. Overlain by calcareous glauconitic sandstone with an Awamoan mollusc fauna.
Fauna:—Brachiopods very abundant, advanced types of Pachymagas and Rhizothyris; molluscs practically absent; forams fairly abundant, good faunas obtained from several of the lithologies present at the type locality.
Correlatives:—(By brachiopods.) Southland limestone at Clifden and other localities); North Canterbury (Main Mt. Brown limestone of Weka Pass). No other localities with the true Hutchinsonian brachiopod fauna are yet known (except possibly in the Trelissick Basin).
Thomson (1926A, pp. 149–151) and others have classed here the Pachymagas greensands in North Otago district, resting with basal conglomerate on eroded phosphatised surface of Kakanui limestone (Whaingaroan), but these contain (e.g., at All Day Bay, Deborah, Devil's Bridge, Rifle Butts, Landon Creek, and Mt. Somers district) less advanced brachiopods, and were considered by Finlay (1939A, p. 530) to represent an older horizon, which is here termed Lower Hutchinsonian. At All Day Bay this horizon, with abundant Pachymagas marshalli, etc., and a basal phosphatic zone containing Isis and Mopsea, rests on eroded Kakanui limestone; it is overlain by a sandstone zone with Waiparia (but no Pachymagas), and this in turn by argillaceous sandstones with Awamoan macro- and micro-fauna.
Thomson (l.c.) has argued that “the contemporaneous existence of species in different stages of evolution is known, and brachiopods are known to be local in their distribution, so that until the two faunules are found in some locality in sequence it is unsafe to conclude that they are not of the same age.” The species of Pachymagas and Rhizothyris erected by Thomson are so very similar inter se and so variable in shape that the actual species present in these various greensands appear to be much less important than the state of evolution of the genus as a whole; simple types certainly accompany the advanced parki and rhizoida in the true Hutchinsonian (as is to be expected), but the really important point is that only the simple types exist in the Lower Hutchinsonia, the later division being marked by the advent of the advanced types. As regards the sequence of the faunas, we believe that Waiparia s.str. is always an age equivalent of the advanced Pachymagas and Rhizothyris, and either exists with or entirely replaces them; if this is correct, the All Day Bay strata provide the sequence Thomson required.
In the typical fauna at Mt. Brown occur Magadina and the restricted Waiparia intermedia-abnormis; the latter species-group is here used to correlate with this the Waiparia zone at All Day Bay, the Waiparia-bearing Caversham sandstone of Dunedin district (Thomson, 1918, p. 197), and the Middle Ihungia brachiopod horizon of Poverty Bay (again with Waiparia abundant, but no Pachymagas). From the three last-named, good foram faunas have been obtained, but the molluscan fauna comes chiefly from the beds above the limestone at Clifden, the Pakaurangi Point beds, the Mahoenui and Ihungia mudstones (deeper water), and the Waitemata Oneroa beds (shallow water, with Magadina) (Powell and Bartrum, 1929, p. 395). Forams also allow correlation with the Lower “Blue Bottom” of Marsden and other localities in Westland, where there are no molluscs or brachiopods.
Although the molluscan beds at Clifden lie above the parki limestone, faunal comparisons between them (up to as far as the “Stethothyris zone”), and the Middle and Upper Ihungia and Pakaurangi Point beds indicate that they still fall within the Hutchinsonian. When the Tertiary as a whole is considered, a separate division of stage value does not appear to us to be warranted for these beds. Finlay (1939A, p. 530) mentioned that a small new stage might be needed here, but much additional information from micro-faunas, accumulated since, negatives the idea. Allan (1940, p. 289) has again suggested that this horizon merits a stage name, but no definite correlation can be made with it elsewhere, and it would have to be postulated as missing or unrecognisable in all other, apparently normal, sections. Such theoretical “stages,” based on rather thin deposits in the South Island, do not merit serious consideration unless they can be usefully employed in connection with much thicker and more continuous beds in the North Island.
For a number of cogent reasons, no new stage name is here proposed for Lower Hutchinsonian as distinct from the True Hutchinsonian, but for convenience the faunal analyses are presented separately. The term “True” is used rather than “Upper” Hutchinsonian to avoid confusion with Park's usage of the latter.