New Zealand Foraminifera: The Occurrence of Rzehakina, Hantkenina, Rotaliatina, and Zeauvigerina.
[Read before the Wellington Philosophical Society, October 11, 1938; received by the Editor, October 11, 1938; issued separately, March, 1939.]
The four genera which form the subject of this paper are of more than local interest. During 1933 they were found at numerous localities in the Poverty Bay district; until then they had not been recorded from New Zealand. With the exception of Rotaliatina, they all occur in deposits older than any from which Chapman received samples. Hence, though often abundant, they are not noted in his bulletin (1926). He saw no real Cretaceous from New Zealand, though he recorded as such various samples from Eocene to Upper Oligocene, and the very little Eocene he had was too hard to yield these forms. Parr has since found some of these genera in Eocene material from Pahi, where I have known them for some years.
Wherever they occur throughout the world these genera are regarded as of small vertical range, and their few species are used as important index forms of the Upper Cretaceous and Lower Tertiary.
Genus Rzehakina Cushman, 1927.
Rzehakina epigona (Rzehak) is an abundant and characteristic index fossil of the uppermost Cretaceous in New Zealand, but seems somewhat local in its distribution. Outside of the Poverty Bay area it is seldom found and has not occurred in coeval deposits in the South Island. Cushman (1933, page 97) gives its range as Upper Cretaceous and doubtfully lowest Eocene, while Galloway (1933, page 97) inclines to regard all its recorded occurrences as Upper Cretaceous. Macfadyen has fully discussed its occurrence in South America (1933, pp. 1–16) and presents the evidence for and against its Eocene occurrence, leaving the matter still somewhat in doubt. It was originally described from Moravia, but the supposed “alttertiar” age of the deposit is almost certainly erroneous, the accompanying Pseudotextularia varians being regarded as one of the best indices of Upper Cretaceous age. However, the Mexican Velasco, in which Rzehakina has long been known, is now regarded as earliest Tertiary (Palaeocene) by Thalmann (Proc. Geol. Soc. Am. for 1934, p. 371, abstract).
In New Zealand it occurs over a fair range of horizons. Its lowermost limit is unknown, as it is present (though rarely) in the lowest beds from which foraminifera have been obtained; these indicate quite definitely an Upper Cretaceous age. Its upper limit is also somewhat in doubt, so that its New Zealand occurrences unfortunately still do not settle definitely whether it enters the Tertiary. It has been found several times in a fauna of undoubted Eocene age, but its possible derivation from lower beds is in each case open to
question. Since few detailed accounts of its occurrence have appeared, and as its index value is of considerable importance to local and even outside workers, a complete list of its known New Zealand occurrences is here presented. The variety lata Cushman and Jarvis (1928, p. 93; pl. 13, figs, 11a, b) described from the Upper Cretaceous of Trinidad has not been separable so far in New Zealand. It was stated to be more rounded and much larger than the typical Velasco form, and New Zealand specimens can certainly be matched with the description and figure, but in these features such enormous variation is obvious at any locality yielding a large enough suite that no good purpose is seen here at present in separating any variation from epigona. New Zealand specimens exactly agree with Rzehak's original figure. Variation does not seem to have any stratigraphic use and occurs at all horizons; two forms are found at most localities, a thick one and a smaller angular and very thin one (microspheric?) with more coils. No specimens in New Zealand, however, approach the thickness of Silicosigmoilina Cushman and Church (1929, p. 502, pl. 36, figs. 10, 11, 12), the extremely similar genus which is common in the Californian Upper Cretaceous Chico, and “occupies the same place in the fauna that Rzehakina does … in Trinidad.”
The earliest records are from the “Puketoro” formation, which is probably equivalent to the Raukumara of the Survey. Mudstone at the top of the “Puketoro” (probably equivalent to the Mangataone) has yielded a few faunas—the only ones in New Zealand with true Globigerina cretacea—; two of these (3201 and 3203, Puketoro Stream) yielded one specimen of Rzehakina, while another (3180, Waitahaia River) did not. None were found in the red beds at the top of the Puketoro (3204), nor in Raukumara beds with Inoceramus in the Dannevirke area (5293 and 5302), but one specimen was again present in mudstone with Inoceramus (5109A, 15 miles south of Cape Kidnappers). In the Raukumara, Rzehakina is thus so rare in records and specimens that it is probably just becoming established in this faunal province.
The next formation, in contrast, provides abundant records and examples. The formational name Rakauroa was used in Poverty Bay for a sequence of beds between Puketoro and undoubted Tertiary; the lower part of this was noted in Hikurangi and Mata survey districts as extensive conglomerates and other coarse sediments—this is quite possibly equivalent to the Tapuwaeroa of the Survey Rzehakina is here abundant, with frequent large, stout specimens of the lata form (e.g., localities 3242 Mata S.D.; 3249 Waipiro S.D.; 3270 Mangaoporo S.D.; also in associated black shales). It is again abundant in coeval deposits from the Dannevirke area (5301, 5321, 5336 and many others), but it is not present in what is evidently a fauna of the same age from the South Island East Grey District (5329, mudstone below Amuri limestone).
The upper, more typical, Rakauroa consists of finer grained, lighter coloured sediments, which are probably in part at least equivalent to the Survey's Whangai. In the Dannevirke area the argillites and chocolate shales of the Whangai have yielded no Rzehakina, but
odd specimens have been found in Poverty Bay samples lithologically referred to the Rakauroa, and it was abundant at locality 3250A (Waipiro S.D., light mottled marls, Tuparoa Stream; above lower Rakauroa conglomerates).
The succeeding formations are Tertiary. The lowest of these is the Te Hua series in Poverty Bay, equivalent to the Survey's Wanstead in Dannevirke. No true Wanstead or younger fauna has ever yielded Rzehakina, nor have South Island beds of equal age. It is missing in the whole Hampden section from the Cretaceous Katiki and Moeraki series through to the Bortonian (equals Wanstead) Kakaho marls. The red shales, however, provide the biggest problem, especially with regard to the possible Tertiary occurrence of this genus. No other beds in this series (chalky limestone, Te Hua marls, etc.) contain it, nor is it present in the whole series of cores from Waitangi No. 1 well, which seemingly pass through all the varieties of red and green shales and bentonitic earths met with on the surface; the faunas here are all typical Bortonian. But at two surface outcrops of red shales in the Waitangi fault zone (4012 and 1006) faunas were found which somewhat resemble the well cores, except in lacking calcareous species and in possessing abundant Rzehakina and Bolivinopsis spectabilis (Grzyb.). The latter species almost invariably accompanies Rzehakina and has much the same range, but seems to be more widespread. I can see no appreciable difference between this species, as figured from Burdwood Bank by Macfadyen (1933, p. 7, Fig. 1c, d, i, j), and the Trinidad shells identified as the later clotho (Grzyb) by Cushman and Jarvis (1932, p. 43, Pl. 13, Figs 5, 6), though Cushman (1934, p. 42, 43) left them separate. Both are very large and have the same accompanying fauna, and the New Zealand forms are certainly the same as the Burdwood and Trinidad ones. The other elements in the Waitangi red shales could easily be of Rakauroa age, so that either these and Rzehakina range into the Tertiary if the outcrops are correlated with the definitely Bortonian well cores, or else there is more than one “red shale.”
The variability of Bolivinopsis in New Zealand is so great that the forms are difficult to deal with. In the chocolate shales at the very top of the Rakauroa (above the White Argillites) and in the Moeraki beds below the Hampden Bortonian there are irregular and distorted specimens with slightly shorter chambers, apparently exactly the same as the Californian Upper Cretaceous B. californica Cush. and Campbell (Contrib. Cush. Lab., vol. 10, pt. 3, p. 70). But some of the New Zealand shells also recall “Spiroplectammina” mexiaensis Lalicker (l.c., vol. 11, pt. 2, p. 43), which is surely congeneric. And the separation from megalospheric spectabilis, even of B. eocenica Cushman and Barksdale, lately recorded by Parr from the West Australian Eocene, does not seem at all sure. A form quite like the Moeraki specimens, and also spectabilis, has been figured by Nuttall (Journ. Pal., vol. 9, pt. 2, p. 125) from the Eocene of Venezuela.
Since this was written I had an opportunity to collect samples from two further bentonitic surface outcrops; 5392 (grey shale directly below basal Wheao conglomerate, Mangatu River) and 5391
(red shale below road level, Armstrong road, Waitangi district). Besides the usual facies background of such forms as Haplophragmoides coronata, Rhabdammina and Hyperammina fragments, Glomospira corona, Cyclammina, Ammodiscus, etc., Bolivinopsis spectabilis and Rzehakina occur in both, though the latter is rare in 5392; an important addition in both is a number of calcareous species, which are too indefinite to refer positively at present to Cretaceous or Eocene, but which are not the well-core species, and show that the faunal differences are not just due to leaching out of the limy forms. One surface outcrop, however, has been seen (1015; Branch D of Red Shale Stream, Waitangi) which contained a Bortonian fauna as in the well cores; Eocene species of Globorotalia, Pulvinulinella and Rotaliatina were present, but no Rzehakina or Bolivinopsis. In the Puketoro Stream section is 1000 ft. of marl and red shale (3209) with a fauna poor in extent but undoubtedly equivalent to those of the well cores, and like them possessing B. spectabilis, but lacking Rzehakina; it lies definitely above 800 ft. of Rakauroa argillite containing Rzehakina (3206). The existence of two red shale horizons thus seems very probable.
Two other localities yielded Tertiary faunas accompanied by Rzehakina. At Pouawa Dome (3286) a fauna was obtained from below another fauna which was Oligocene. The Oligocene fauna (3287) was slightly contaminated with specimens from the older bed; the latter had a predominately Wanstead fauna, but included three or four species such as Rzehakina, B. spectabilis, etc., which differed in preservation and were almost certainly derived from a still lower horizon in this complicated fault structure. The other locality (4019) was at Te Hua Stream, Waitangi, where the Wanstead fauna also showed Rzehakina and B. spectabilis but, as red shales were closely associated, it seems likely that again derivation occurred. Three further localities, 3284A (Pouawa Dome), 3290 (Whangara uplift), and 4013 (Waitangi uplift) yielded Rzehakina with calcareous species which are possibly Bortonian, but may be Cretaceous; they are all in disturbed areas, and are unlikely to yield pure faunas.
Apart then from the red shale question, it is evident that Rzehakina in New Zealand, especially when abundant, denotes Rakauroa age (Whangai plus Tapuwaeroa?), that it extends feebly to the underlying Raukumara, and that its appearances in overlying beds are all doubtful.
Outside of the Poverty Bay and Dannevirke areas Rzehakina is very rare. This may be owing to the absence of suitable lithologies. Yet the variety of facies in the Rakauroa carrying abundant Rzehakina is considerable (conglomerates, sandstones, black shales, siliceous marls, bentonitic red shales, etc.). Some of these facies of suitable age certainly occur elsewhere in New Zealand, but the only other locality where an occurrence is known is 1283, near Silverdale, North Auckland. Here it is not uncommon and genuinely part of the fauna, which comes from a hydraulic limestone area and though that formation is Wanstead Eocene, it seems to be from an underlying Cretaceous horizon. The rest of the fauna is rather similar
to that of the Rzehakina red shales. In the large undoubted Wanstead faunas from the Pahi greensands and associated marls there is no trace of this genus, though the lithology appears very suitable; a deceptively similar poorly preserved form does occur, but it is evidently calcareous and probably a Massilina.
The above discussion relates to the species epigona; the genus itself, as a related form, R. venezuelana Hedberg (1937, p. 669), has been recorded from well up in the Tertiary; it is not unlike the thinner form of epigona already mentioned.
Genus Hantkenina Cushman, 1924.
Hantkenina australis n.sp. (Plate 69, fig. 5).
A fully satisfactory description of this species cannot yet be given, as no well preserved, unbroken examples have yet been found. Though it occurs at a number of localities, it is generally so rare and fragile that a composite description must be drawn up from a number of specimens. The genus is, however, of such interest and importance that the record is made in spite of this.
The species is best described by comparison with H. alabamensis, the genotype, which it most nearly resembles. It has similarly compressed chambers but the sutural gutters are deeper and more marked. No examples have been seen with other than five chambers. The spine, as in alabamensis, is directly adjacent to the next suture (not as in mexicana and its allies quite distant from it); it is of about the same relative length when unbroken (as long as or longer than the distance from its base to the umbilicus) but instead of being practically straight as in alabamensis, it usually has a decided backward curve. A notable difference is that the succeeding chamber begins at the base of the spine at the same level as the previous one and does not start some distance up the spine, as is usual in alabamensis. The aperture is similar to that figured by Cushman (1924, p. 3) but is narrower and the basal wings are distinctly less spread, diverging at less than 90°, instead of considerably more.
The figured specimen was the best then available and is from Waitangi No. 2 well, 1560 feet. It has the surface badly preserved, has evidently suffered distortion, shows the chambers much too swollen and the spines broken, though the other details mentioned are the same. It measures 0.6 mm. in diameter (without spines) and 0.3 mm. in thickness.
The type (which will be figured later) has been chosen from the Hampden section, locality 5179B (1¼ miles North of Kakaho Creek, upper blue clays, about 5 feet below the top)—an Upper Bortonian horizon. Five damaged but uniform specimens were found showing some perfect spines and a highly polished surface, minutely but distinctly perforate.
This species appears to be limited to the Upper Bortonian. Besides the two localities mentioned, it occurs at 3310 (Pahi marl, with Zeauvigerina), 5319 (Mangaotoro S.E. Survey District, 1 mile 31 chains at 180° from trig U).
The Eocene species recorded from Mexico by Nuttall (1930, p. 272) have little similarity to the New Zealand form, with the possible exception of H. longispina, but this has a more open umbilicus, a lohulate periphery and a spine, though of similar length, not quite adjacent to the following suture.
Genus Rotaliatina Cushman, 1925.
Though this has not previously been recorded from New Zealand, a typical species has been known for many years, under a wrong generic location. This is Rotalia sulcigera Stache, 1864 (Reise der Novara, Pal. vol. 1, page 275, plate 24, figs. 25a, b, c, d), of which the next described species Rotalia naticoides Stache (l.c. page 276, plate 24, figs. 26a, b, c, d) is an exact synonym. Stache's idealised and erroneous figuring of the sculpture and aperture has been responsible for subsequent confusion and inability to locate this common New Zealand species. Chapman, as evidenced by his slides, did not understand it and identified examples as Cassidulina and Gyroidina; in his New Zealand Bulletin he was unable to synonymise the names and retained them both as species of Rotalia of the soldanii type.
In the plentiful faunas that have now been examined from the Whaingaroa and equivalent series this shell is only occasionally absent and is usually quite common. Very fine specimens have been observed abundantly in the West Coast Point Elizabeth beds. Indeed, throughout the Ototaran sequence in quite varied lithologies this is a striking index fossil. It is absent, however, from such muddy and glauconitic deposits as Wharekuri and Chatton; but its occurrence in argillaceous glauconites elsewhere indicates that this is probably an age not a facies absence.
The species is not confined to the Ototaran, but also occurs, usually much more rarely, throughout the Eocene, at least down to the lower Bortonian. Small specimens are fairly frequent in Waitangi No. 1 well, cores 9 to 16. It is also present as large typical specimens in the Cheviot chalk marls at the base of the Amuri limestone (with an upper Bortonian fauna) and at Pouawa Dome, Poverty Bay (with a lower Bortonian fauna).
Its upper range is, however, strictly limited to the Ototaran and, though abundant in the upper parts of this formation, it has never been seen in hundreds of samples from the overlying Hutchinsonian and later beds; it has not even been found so far in the intervening Duntroonian and Waitakian stages. It is thus an excellent marker for the Oligocene and Ototaran when associated with post-Eocene elements (certain species of Globigerina, Cibicides, Uvigerina, etc.). Its occurrence, sometimes in abundance, at several localities in the Poverty Bay “Maungatapere” formation is part of the definite evidence for referring this stage to the Upper Ototaran (middle Oligocene). The Te Kuiti and Cobden limestones are so hard that only poor faunas can be obtained from them, but large specimens of Rotaliatina sulcigera are almost always present in the latter, but disappear in the grading beds above it.
This seems a suitable place to point out and correct an error regarding the Whaingaroa formation which has been world-wide ever since Stache described its fauna in 1864. Every subsequent author seems to have accepted without question his dictum as to its Eocene age. Cushman and Dusenbury, for example (1934, page 52), identified several Eocene Californian species with these supposedly Eocene New Zealand forms; several other workers have made similar comparisons and as late as 1937 Cushman and Parker (1937, page 66) took the age of topotypic Whaingaroa material as Eocene. Even in Australia this opinion has been prevalent; Chapman, with little relevant material, quoted Upper Eocene in his New Zealand Bulletin, and Parr and Collins (1937, pp. 190–211) quite recently discussed the Whaingaroa Polymorphinidae in terms of this age. In a later note, quoted in a paper by Bartrum (1937, p. 436), Parr has been the only writer to amend this conclusion and suggest a Lower Oligocene age. In 1933 I had written him stratigraphic notes on the succession in Poverty Bay, pointing out that much Tertiary still underlay beds coeval with the Whaingaroa, and his examination of a definite Eocene fauna from North Auckland made him realise that Stache's conclusions must be wrong. Stache's error was pardonable at the time, as he had no New Zealand comparative material and no knowledge of the stratigraphic column; it is only by intensive comparison with standard sections from many places in our Lower Tertiary that the Whaingaroa can be accurately placed. It is, as a matter of fact, Upper Ototaran, which is probably Middle Oligocene. Well defined faunas of the underlying Waiarekan and Lower Ototaran and the overlying Duntroonian and Waitakian (all stages of the Oligocene) are known in sequence at several localities, and the relation of the Whaingaroa fauna to the Eocene is but slight. The evidence for all this will be elaborated elsewhere—but the current misconception of the “Novara” fauna should be rectified.
The species Rotaliatina sulcigera (Stache) (plate 69, figs. 6, 7) is an extremely variable one in size, shape and height of spire, but has a general strong resemblance to mexicana, the genotype. This was from the lower Oligocene Alazan shale. Nuttall (1930, p. 272) has recorded it also as common in the upper Eocene Chapapote and rare in the middle Eocene Guayabal. This roughly corresponds to its New Zealand range. The apertural and sculptural characters appear much the same in the two species, but the New Zealand form is readily distinguishable by its more numerous chambers, having almost always nine (very occasionally eight to ten), instead of seven in a whorl.
Besides the Eocene and Oligocene forms, a species has recently been described from the Pliocene of West Java. This is R. globosa, Yabe and Asano (see 1937, page 124, plate 19, fig. 7). The authors remark that “This is a large species. … The raised and granulated sutures are of peculiar type … .” The size—about 2 mm.—is in fact enormous for the genus and the whole appearance of this Pliocene form shows plainly that it is derived from typical Javan species of Rotalia, such as schroeteriana P and J., and especially alveiformis Thalmann. It is really a form of the latter in which the
dorsal surface has become excessively raised and the base has descended, just as true Rotaliatina is a development along similar lines from Gyroidina. These differences in each case may seem slight, but go hand in hand with such obvious constancy and much more limited stratigraphic range that generic distinction is fully warranted. Apart from pronounced sculptural and size differences, globosa shows its distinction from Rotaliatina proper in its aperture, which is not the long, narrow Gyroidina slit, but is much more concentrated and open basally, as in the species of Rotalia mentioned. It is also non-umbilicate, as they are, while an umbilicus is one of the generic features of Rotaliatina and Gyroidina. The discontinuous record of the lineage would itself arouse suspicion, for true Rotaliatina apparently died out in the Oligocene, and the present case is evidently only another of the many examples of convergence. The Javan shell merits separation for the same reason as its earlier prototype and I accordingly propose the new genus Asanoina, with genotype Rotaliatina globosa Yabe and Asano.
An attempt was at first made to separate the New Zealand Eocene forms specifically but this was found to be impossible. All variations in size, shape of shell and chambers, height of spire, formation of apertural face and umbilical area found in the Oligocene formations can be matched at different localities in the Eocene and no practical discrimination can be made. The nearest actual specimens to Stache's figures are from locality 5231 (Waitetuna Estuary, 1 mile North of junction with main Raglan Road, 15 chains past limestone outcrop); these will be figured in a later paper. Figures 7a, b on Plate 69 are from Upper Ototaran specimens coeval with Stache's (locality 1242, Awakino River, marls below limestone on road 7 miles up river from village); figures 6a, b are from Upper Bortonian specimens from Waitangi No. 1 well, core 9.
Genus Zeauvigerina n.gen.
Genotype Z. zelandica, n.sp.
Genus similar to Eouvigerina in size, biserial arrangement of most chambers and spout-like uvigerine aperture, but differing in first and last stages. The early chambers show not the slightest trace, even in the microspheric form, of spiroplectine coiling; the final chambers have no tendency to become irregularly triserial, the whole test being regularly bolivine throughout.
The general similarities to Eouvigerina (especially of the aspera and gracilis type, which have somewhat the same ornament) are so marked that close relationship must surely exist. If so, the elision of the theoretical coiled early chambers and the more settled and compact development throughout is probably due to the later appearance in time of this genus, Eouvigerina proper being an Upper Cretaceous form, while the New Zealand development is Upper Middle Eocene.
Zeauvigerina zelandica n.sp. (Plate 69, figs. 4a, b).
Test minute, even for the genus. Microspheric form larger, fairly regularly and acutely tapering, about eight chambers on each side and a small distinct proloculum, perfectly terminal and with no trace
of coiling. Megalospheric form shorter and less acute, with a tendency towards a change in the angle of tapering on one side at lower third, about six chambers on each side. Greatest width usually across last two chambers, but sometimes the sides below this almost sub-parallel. Considerable variation in outline and proportions. Early chambers usually considerably compressed in microspheric form, of equal inflation with the later ones in megalospheric. Adult chambers sub-globular, somewhat compressed from front to back, and closely knit at sutures, which are never more than shallow grooves and frequently almost obscured by ornament; they are not quite horizontal, but the angle is slight; a similar medial, undulating, shallow groove where chambers meet. There is never any trace of separation of the later chambers as in Eouvigerina gracilis Cushman. Final chambers not triserial, the whole structure of the shell being bolivine. Aperture rising abruptly from ultimate chamber where it meets penultimate, medial in position, a relatively stout and large tube with a fairly broad, phialine lip, sometimes very short or obscurely developed and occasionally very long and some part of it bent out of line of shell. Whole surface regularly and minutely studded with very fine papillae producing a roughened but glistening surface; sutures smoother and neck when long occasionally with last part smooth, but the papillae usually run right up to it.
Length 0.27 mm.; breadth 0.175 mm.; thickness half to two-thirds width.
These are the dimensions of the figured specimen, which is from locality 3310 (greasy marl, interbedded with greensand, 1 mile Northwest of Pahi, Paparoa Arm, Matakohe Survey District). Since the figure (which gives quite a fair idea of the species) was drawn, better preserved specimens have been found from a locality where the sequence of beds is also much clearer. The holotype is accordingly taken from locality 5300 (Moeraki N.E. Survey District, 1 mile at 29° from trig E, “marly clay” of McKay), and will be figured in a later paper. The latter locality is the highest of a sequence of beds—the Hampden or Kakahoian glauconitic marls—all definitely Bortonian (Eocene). This sequence can be subdivided but Zeauvigerina has not been found in the middle or lower parts. Also, in numerous other localities it occurs always associated with upper Bortonian species. It can be taken, therefore, as a good index of Upper Middle Eocene age, as distinct from the lower Bortonian, which is probably still middle Eocene.
The species is a characteristic one of the Wanstead horizon and occurs at numerous localities of this age in the Dannevirke and adjoining districts. It is also present in some of the chalk marls at the base of the Amuri limestone (e.g., Hurunui Mouth, left bank of river, first outcrop upstream from mouth) and incidentally proves the whole of the Amuri limestone in this area to be Tertiary and not older than Upper Eocene. It is again present at several places in the Te Hua marls of the Waitangi fault area and coeval beds in the Poverty Bay district, which are thus definitely referable to the Bortonian and cannot be Cretaceous in age.
New Names Proposed.
Zeauvigerina n.gen. (Fam. Heterohelicidae). Genotype: Z. zelandica n.sp. (Upper Middle Eocene).
Asanoina n.gen. (Fam. Rotaliidae). Genotype: Rotaliatina globosa Yabe and Asano (Pliocene).
Hantkenina australis n.sp. (Upper Middle Eocene).
Zeauvigerina zelandica n.sp. (Upper Middle Eocene).
List of references.
Bartrum, J. A., 1937. The Greensand-Hydraulic Limestone Contact at Pahi, Kaipara, N.Z. Journ. Sci. and Tech., vol. 19, no. 7.
Chapman, F., 1926. Cretaceous and Tertiary Foraminifera of New Zealand, Geol. Surv. Pal. Bull, no 11.
Cushman, J. A., 1924. A New Genus of Eocene Foraminifera, Proc. U.S. Nat. Mus., vol. 66, art. 30.
— 1933. Foraminifera, Cush. Lab. Foram Research, special publication no. 4.
Cushman, J. A., and Dusenbury, A. N., 1934. Eocene Foraminifera of the Poway Conglomerate of California, Contrib. Cush. Lab. Foram Research, vol. 10, pt. 3, no. 145.
Cushman, J. A., and Jarvis, P. W., 1932. Upper Cretaceous Foraminifera from Trinidad, Proc. U.S. Nat. Mus., vol. 80, art. 14.
Cushman, J. A., and Parker, F. L., 1937. Notes on Some of the Early Described Eocene Species of Bulimina and Buliminella, Proc. U.S. Nat. Mus., vol. 13, pt. 3, no. 187.
Galloway, J. J., 1933. Manual of Foraminifera.
Macfadyen, W. A., 1933. Fossil Foraminifera from the Burdwood Bank, Discovery Reports, vol. 7.
Nuttall, W. L. F., 1930. Eocene Foraminifera from Mexico, Journ. Pal., vol. 4, no. 3.
Parr, W. J., and Collins, A. C., 1937. Some Species of the Family Polymorphinidae, Proc. Roy. Soc. Vic., vol. 50 (N.S.), pt. 1.
Stache, G., 1864. Die Foraminiferen der Whaingaroa-Hafens, Reise der Novara, Pal., vol. 1, art. 5.
Yabe, H., and Asano, K., 1937. Minute Foraminifera from the Neogene of West Java, Sci. Rep. Tohoku Imp. Univ., ser. 2, Geol. vol. 19, no. 1.
Hedberg, H. D., 1937. Foraminifera of the Middle Tertiary Carapita Formation of North-eastern Venezuela, Journ. Pal., vol. 11, no. 8.