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Planktonic foraminiferal analyses of six deep-sea sediment cores from the central North Atlantic east of the Azores Islands between 37°N and 40°N show distinct oscillations in planktonic foramineferal assemblages during the last 300,000 years. A paleoclimatic curve has been constructed using “Total Fauna Analysis” that reveals three glacial and four interglacial episodes. Relatively minor climatic oscillations are superimposed upon the major glacial-interglacial episodes. The paleoclimatic curve is similar to previous paleoclimatic curves from the Atlantic and adjacent areas. Minor paleoclimatic fluctuations are more distinct in paleoclimatic curves from high latitudes of the Atlantic. The faunal assemblages are transitional between subarctic and subtropical assemblages. During portions of the interglacial episodes, the assemblage is dominated by Globorotalia inflata. Neogloboquadrina pachyderma (dextral-coiling) or Globigerina bulloides dominate during the remainder of the interglacial episodes and during the glacial episodes. Glacial episodes are also marked by particularly high frequencies of Globigerina quinqueloba and Globorotalia scitula. Interglacial episodes are also marked by increases in Globorotalia truncatulinoides, Globigerinoides ruber, and Globigerinella aequilateralis. The planktonic foraminiferal faunal oscillations in the cores are complex and cannot be entirely explained by temperature variation. Other parameters such as salinity, nutrients and biological competitin must influence the faunal oscillations. The faunas suggest no major planktonic foraminiferal faunal boundaries migrated across the area between 37°N and 40°N in the central North Atlantic during the last 300,000 years.

A population of Globigerinoides considered to be an early stage in the primordius altiaperturus trilobus complex has been discovered in the lower part of the Waitakian Stage.

The carbon isotopic composition of three phenotypes of Globigerinoides ruber, which deposit their shells at three different depths in the water column, reflects the changes in δ13C of the dissolved bicarbonate. The variations are in agreement with the interpretation of increased biological activity in the surface waters compared to the deeper waters. The carbon isotopic composition of Orbulina universa is not in isotopic equilibrium with the dissolved bicarbonate, even though the oxygen isotopic composition of this species is deposited in isotopic equilibrium.

The principal component analysis method is applied to the study of associations of different Pleistocene and Holocene planktonic Foraminifera in five cores from the eastern Mediterranean. Comparison of the fossil foraminiferal distribution with the distribution of living species leads to grouping of the fossil microfauna on the basis of paleoecological controls. Factor 1 is interpreted as representing thermal control. We recognize as warm-water species Globigerinoides trilobus, Globigerinoides trilobus sacculifer, Orbulina universa, Globigerinella siphonifera, Globigerinoides ruber. Cold-water species are Globigerina pachyderma, Globorotalia scitula, Globigerina quinqueloba, Globigerinita glutinata. Species considered to be of intermediate character are Globigerina bulloides, Globorotalia inflata and Globorotalia truncatulinoides. Factor 2 also leads to the grouping of these last species and may reflect the contributing influence of productivity phenomena. A quadratic liaison interpreted as the “Guttman effect” relates factors 1 and 2. Factor 3 introduces complications resulting from apparently sporadic, irregular events affecting the distribution of certain species, notably Globoratalia inflata, Globorotalia truncatulinoides and Globigerina dutertrei.

Variations of foraminiferal abundance in sediments deposited in shallow oceanic depths may give relatively accurate indications of the surface ecology at the time of deposition. In deeper realms such variations are largely a product of differential solution among the species. This leads to preferential enrichment of resistant, deep-dwelling species (Globorotalia tumida, Sphaeroidinella dehiscens, Globigerina eggeri, and Pulleniatina obliquiloculata) and to selective elimination of fragile, surface-inhabiting individuals (Globigerinoides ruber). The shallowest depth at which differential solution is effective in Equatorial Atlantic sediments is at present 4000 m. Most faunal assemblages in depths greater than 4500 m are differentially dissolved, and in depths greater than 5000 m all show severe effects.

SYNOPSIS. Globigerina bulloides and Globigerinoides ruber, two pelagic foraminifera from the North Atlantic, were fixed in modified Zenker or Bouin solutions directly after collection and studied cytochemically. They have two unusual organelles: a vesicular system and an organelle provisionally named a “cryptosome.” The vesicular system occurs chiefly in the newest formed chambers and consists of a pair of intertwined tubules with helical fine structure which terminate in a bouquet of approximately 20 vesicles or loops. The function of this system is unknown. The detailed morphology of the vesicular system is different in each species. The cryptosome is a structure which varies greatly in its morphology. It is better developed in G. bulloides than it is in G. ruber. At times a cryptosome may occupy up to 2/3 of the protoplasm of a chamber. In Himes-Moriber-stained preparations crypto-somes stain with naphthol yellow S and contain within them an azure A-Schiff staining spongy reticulum. Both of the pelagic foraminifera studied are heterokaryotic. Agamonts of G. ruber may have a graded series of nuclear sizes but those of G. bulloides typically have a single somatic nucleus. The zooxanthellae of G. ruber are similar to Symbiodinium microadriaticum and may collectively occupy almost 4/5 the volume of a chamber.

A core, 365 cm long, was taken at a depth of 4420 m in one of the depressions located at the South of Cape Matapan (Ionian Sea). It reveals, at 40 cm below the top, alternations of white and red muds. The white muds coincide with the higher percentages of the Foraminifera belonging to the Globigerinoides trilobus groupe, with local occurrence of the tropical species Sphaeroidinella dehiscens . Clay minerals in the same levels are characterized by attapulgite, which is interpreted as the result of a neoformation in a basic-chemical environment. The age of such unusual warm marine deposits is probably not younger than Tyrrhenian (Riss/Wurm interglacial).

Sixty-six benthic and 21 planktonic species are listed from a sample of globigerina ooze taken at 470 fathoms from a seamount on the eastern flank of the Tonga Trench. The fauna as a whole is a typically warm-water modern one. It is composed mainly of planktonic forms, with species of Globigerinoides dominating the assemblage. The present-day benthic species appear to be normal for the bathyal zone. Some older-looking, stained, and worn specimens could be of Plio-Pleistocene age.

Apertural dimensions of Globigerinoides from the lower Miocene Globorotalia kugleri — Globigerinatella insueta zones of Trinidad and Otaian-Altonian stages of New Zealand are closely similar at equivalent stratigraphic levels. Nomenclatural and stratigraphical confusion which affects the application of Bandy’s “Globigerinoides trilobus datum” is possibly resolvable by restricting G. trilobus trilobus (Reuss) to low-apertured populations. In both regions these can first be distinguished about the level at which Globorotalia scitula praescitula Blow appears (C. stainforthi zone; Hutchinsonian-Awamoan stages). So defined, the advent of G. trilobus trilobus may itself provide a useful homotaxial datum which should be distinguished from the initial appearance of the Globigerinoides trilobus group in the lower Miocene as the high-apertured G. trilobus altiaperturus Bolli (G. kugleri zone; Otaian stage).

Measurements on Globigerinoides trilobus trilobus (Reuss) suggest that rate of chamber expansion is a useful criterion of stratigraphic position in the Awamoan-Altonian Stages (New Zealand), and Catapsydrax stainforthi — Globigerinatella insueta Zones (Trinidad), that may avoid current difficulties in the use of G. t. trilobus and G. bisphericus as homotaxial markers. Angle of attachment of the final chamber, extent to which this chamber envelops the rest of the test and shape of the primary aperture show local trends but are less useful for inter-regional correlation within the interval studied.

Usages of Hutchinsonian, Awamoan and Altonian Stages are traced. The validity of foraminiferal criteria for the stages is reviewed. Those for the Hutchinsonian: Awamoan and Awamoan:Altonian boundaries appear to be unsatisfactory when compared with trends in Haeuslerella and Globigerinoides. There is partial overlap amongst name bearers for the stages. Proposals to emend the classification will be made in a subsequent paper.

Implications of Allan's redefinition (1933) of the Awamoan Stage are assessed using stratigraphic trends in the lineages of Haeuslerella pukeuriensis Parr and Globigerinoides trilobus trilobus (Reuss) observed in the section at “Old Rifle Butts”, Oamaru. The redefinition lowers the base of the stage as set by Thomson (1916), but complete overlap with Hutchinsoniancannot be shown. The highest unit at “Old Rifle Butts” (Allan's name bearer) may be lower than that implied in Thomson's usage of Awamoan. The lowest formation in the Altonian name bearer (Clifden Limestone above Lower Limestone Member, Clifden) is probably equivalent to Awamoan of Allan (1933) and to Hutchinsonian (part) and Awamoan of Thomson (1916).

Globigerinoides from the Globigerina c. ciperoensis-Catapsydrax dissimilis zones in the Caribbean are compared with an Otaian sample from northern New Zealand using measures of rate of chamber expansion, angle of chamber attachment, envelopment of earlier chambers by the last-formed, and aperture shape. Mahalanobis’ D 2 and canonical analyses show that the Otaian sample is more similar to material from the G. dissimilis zone than to that from the Globorotalia kugleri zone, Trinidad. Relations between a Cuban G. c. ciperoensis zone sample and material from Trinidad and New Zealand differ from that expectable within a set of samples from a single stock.

Tertiary sediments exposed in the central Oregon Coast Range were examined for calcareous nannoplankton and planktonic Foraminifera. Twenty-one samples were obtained from the Tyee, Yamhill and Nestucca Formations, the unnamed siltstone at Alsea Bay, the Yaquina Formation, and the Nye Mudstone. These formations previously have been correlated with the Ulatisian through Saucesian microfaunal stages recognized in California. Plankton were recovered from samples of the Tyee Formation, the “siltstone of Alsea” and the Nye Mudstone. The Tyee plankton, including Clavigerinella colombiana, Subbotina bolivariana, Truncorotaloides collactea, and Pseudohastigerina sharkriverensis, have been reported from the Middle Eocene elsewhere. Common planktonic Foraminifera of the “siltstone of Alsea” are Globigerina minima, G. senilis, and Chiloguembelina cubensis. Calcareous nannoplankton include Reticulofenestra scissura, Chiasmolithus cf. C. oamaruensis, and Isthmolithus recurvus. This assemblage suggests correlation of this siltstone with Late Eocene or basal Oligocene of the standard tropical plankton zonation. Planktonic Foraminifera from the upper Nye Mudstone include Globigerina euapertura, G. juvenilis, G. praebulloides, and Globigerinoides primordius, which suggest an Early Miocene age. Characteristically, the plankton specimens show much morphological variation. Generally, the plankton are sparse with lower species diversity than tropical assemblages of similar age. These observations suggest that the site of deposition was perhaps in nearshore areas, isolated from lower-latitude plankton provinces by southward-flowing currents.

A continuous series of 1/2-cm.-thick sections from a pilot core, collected at the top of a small knoll in the equatorial Atlantic have been investigated by a variety of methods. In 1954 the suggestion was made that in this core the carbonate content was a reflection of temperature in the upper layer of the sea. Paleotemperature measurements on the tests of Globigerinoides sacculifera are given for 33 sections. The broad relation between paleo temperatures and rates of accumulation of $CaCO_{3}$ supports this hypothesis. If allowance is made for probable errors, the paleotemperature measurements are not inconsistent with the hypothesis that the secondary carbonate oscillations are also a reflection of temperature change.

Basic andesite at Muriwai, New Zealand, occurs within upper bathyal deposits of the Lower Miocene. Its biostratigraphic position is just below the point of origin of Globigerinoides bisphericus (sicanus) from Globigerinoides trilobus. This is within the Awamoan Stage of New Zealand, it is correlative with the upper Saucesian Stage of California, the Burdigalian of Europe, zone N-7 of Banner and Blow, and it is within the Globigerinatella insueta zone as redefined by Bolli in 1966. The potassiumargon age of 16.8 million years B.P. provides an important datum within the upper part of the Lower Miocene.

The paleomagnetic stratigraphy of 3 deep sea cores from the central North Atlantic ocean indicates that sediments as old as 2 m.y. were recovered. In one of the cores, CHAIN 61 (171), the phylogenetic transition between Globorotalia tosaensis and Globorotalia truncatulinoides was observed within the Olduvai Normal Event. This evolutionary transition also occurs at the base of the Pleistocene in the holostratotype Calabrian of Italy. Assuming a constant sedimentation rate within the Olduvai polarity section of the core, an age of 1.85 m.y. for Plio/Pleistocene boundary is estimated. The major disappearance of discoasters occurs just above the base of the Pleistocene about 1.6 m.y. ago; discoasters were also found in a single sample within the Jaramillo Normal Event about 0.9 m.y. ago and are interpreted to result from sediment reworking. In all three cores a marked increase in abundance of Globorotalia inflata and Globorotalia hirsuta (cool water species) and a corresponding decrease of Globigerinoides ruber and Globigerinoides sacculifer (warm water species) is noted within the Jaramillo Normal Event at about 0.9 m.y. ago. This faunal change probably corresponds to a major cooling trend and may mark the initiation of Pleistocene glaciation in Europe and North America. These ‘absolute’ dates fit well in the recently estimated chronometric time scale of the Pleistocene in the type area.

The δ18O range in Globigerinoides rubra fossils in a Sigsbee knoll core indicates a temperature range of about 5°C for the Gulf of Mexico during the Pleistocene age. By use of the empirically determined temperature dependence of δ13C of photosynthetically fixed carbon and by use of observed values for various sediment cores, a temperature range up to 35°C is suggested. A greater contribution of terrestrially derived light organic carbon during the cold relative to the warm periods may explain the anomalous carbon-isotope-derived paleotemperature range for the Gulf of Mexico.

A drillhole at Awamoa Creek, Oamaru, sited on strata that constitute the name bearer for the Awamoan Stage (lower Miocene), penetrated (in downward sequence) Rifle Butts Formation (c. 55 ft), Gee Greensand (c. 120 ft), and terminated in volcanic agglomerate (?Deborah Volcanic Formation). Correlations with the section at Target Gully (principally by trends in Haeuslerella pukeuriensis Parr, in Globigerinoides trilobus trilobus (Reuss) and in Globorotalia zealandica zealandica Hornibrook) indicate that the latter sequence is highly condensed. Because Target Gully Shellbed, base of the Awamoan Stage by original designation, appears to be strati-graphically superior to strata at Awamoa Creek, the latter is rejected as name bearer. Target Gully Shellbed is proposed in its place.

The first evolutionary appearance of Globigerinoides trilobus primordius (the Globigerinoides datum) has been taken to correspond closely with the base of the Aquitanian Stage at its stratotype, Saucats, south-western France. But elsewhere in Aquitaine basin (Escornebeou) the taxon occurs in strata with miogypsinids that are antecedent to those in the Aquitanian stratotype. Biometric comparison of G. trilobus primordius from these localities supports the miogypsinid data. The Escornebeou population is probably more primitive than those from Saucats: heights of apertures and of the spire are greater and chamber overlap is smaller. The test is less compact. As a precise criterion for the base of the Aquitanian Stage, as judged from the stratotype, the appearance of G. trilobus primordius is unreliable. Its first evolutionary appearance precedes this horizon.

The stratigraphic ranges of 103 species and subspecies of planktonic Foraminifera have been worked out for the Teurian to Waitakian Stages (Danian to Lower Miocene) of New Zealand. A zonal scheme based on these ranges is given and all the 14 zones are defined and discussed in relation to the New Zealand Stages. A corelation has been made with a similar set of zones already established in Trinidad, based on the ranges of taxa common to both areas. The following new Tertiary planktonic Foraminifera are described and illustrated: Chiloguembelina waiparaensis n. sp., Globigerina angiporoides minima n. subsp., Globigerina brazieri n. sp., Globigerina brevis n. sp., Globigerina labiacrassata n. sp., Globigerina pauciloculata n. sp., Globigerinoides inusitatus n. sp., Globorotalia aequa bullata n. subsp., Globorotalia australiformis n. sp., Globorotalia dolabrata n. sp., Globorotalia gemma n. sp., Globorotalia inconspicua aculeata n. subsp., Globorotalia insolita n. sp., Globorotalia munda n. sp. Pseudo...

Oxygen isotopic analysis of different size groups of shells of pelagic foraminiferal species shows that some species deposit their shells at constant depths while others deposit them at increasing or decreasing depths. These patterns show regional variations. Globigerinoides rubra and Globigerinoides sacculifera remain the most convenient species for oxygen isotopic determination of the past surface temperatures of the ocean.

PLANKTONIC foraminifera, numbering about thirty modern species, have been found alive not only near the surface but as deep as 2,000 m (ref. 1). Emiliani2 analysed the O18/O16 composition of the shells of several species and concluded that different species occupy different depth habitats, with Globigerinoides ruber and G. sacculifera living very close to the ocean surface, Globigerina spp. living somewhat deeper and Globorotalia spp. occupying the deepest habitats down to about 200 m for population averages. Whereas O18/O16 analysis of the carbonate shells can only establish the depth at which average shell deposition takes place, not only for individual shells but for entire populations, recent work by Jones3, using opening and closing plankton nets, has shown that the conclusions reached by Emiliani2 are essentially correct. It therefore seems that the average depths of shell deposition are also the average depths at which the different species live.

Reexamination of two samples from southwestern Puerto Rico previously assigned to the Globigerina ciperoensis ciperoensis Zone has identified Globigerinoides trilobus primordius (previously reported as Globigerina praebulloides occlusa). Faunal associations have an Oligocene aspect. Two interpretations for the associations are possible if the zones by Bolli are considered: (1) Globorotalia kugleri is not present for ecologic reasons, and both samples correspond to the G. kugleri Zone; or (2) Globigerinoides trilobus primordius appeared before Globorotalia kugleri and the samples must be assigned to the Globigerina ciperoensis ciperoensis Zone.

The origin of Globigerina bulloides in temperate areas occurs in the middle Miocene in Neogene zones 9 or 10, whereas in tropical sections it appears in the upper Miocene in Neogene zones 16 or 17, a cool-water cycle. In both cases it could be represented as being derived from Globigerina praebulloides. The origin of the temperate Globorotalia (Turborotalia) pachyderma, dextrally coiled, occurs in Neogene zone 13 or just below in temperate areas, whereas it invaded subtropical areas only during the principal cold cycles subsequent to deposition of zone 13. Forms of Neogloboquadrina lacking umbilical toothlike structures such as N. dutertrei subcretacea appeared in tropical and warm temperate areas in the late Miocene. Neogloboquadrina dutertrei dutertrei with umbilical toothlike structures appeared near the end of Pliocene or at the beginning of Pleistocene time in Neogene zone 22 in tropical areas, whereas the primitive forms continued into the Holocene in temperate areas. Thus, there is an apparent extinction datum plane of the primitive form near the end of Neogene zone 21 deposition in tropical areas but not in temperate areas. Coiling characteristics and form ratios distinguish this group from Globorotalia (Turborotalia) pachyderma. Praeorbulina spp. appear initially in the lower Miocene Neogene zone 8 in tropical areas; isomorphs of this genus appear initially in temperate areas in Neogene zones 11 or 12. The earlier forms originated from species of Globigerinoides whereas those in temperate areas appear to have originated from Globigerina. Ecologic-evolutionary relations are responsible for these and many other kinds of time-transgressive aspects of planktonic datum planes. End_of_Article - Last_Page 330

Late Pleistocene and Holocene climatic fluctuations in the Red Sea are reflected in distributional patterns among planktonic foraminifera studied in 20 deep sea cores. Fluctuating percentages in two species, Globigerinoides ruber and G. sacculifer, have allowed the recognition of four biostratigraphic assemblage zones spanning the past 80,000 years. The youngest Zone, A, corresponds to the Holocene (base dated at ca. 11,000 years B.P.) is characterized by the dominance of Globigerinoides sacculifer, and represents the establishment of a normal Indian Ocean fauna following the Wurm glaciation.

The foraminiferal family, Miogypsinidae, contains evolutionary series, the successive units (species) of which are common to the Louisiana Gulf Coast, Florida, the Caribbean region, and the Mediterranean region. It is suggested that the miogypsinids had a monophyletic origin and that dispersal of some of the evolving groups during the Oligocene and the Miocene was a rapid process. Stratigraphic relationships between miogypsinid species and planktonic Foraminifera in the Gulf Coast offer the key to world-wide correlations and proper use of some of the European terminology. Oligocene sediments on the western side of the Atlantic contain the probable Rotalia ancestors of the Miogypsinidae, which show only slight differences from widely distributed primitive Miogypsinidae. Chattian beds in both the Old and the New World contain the primitive Miogypsina complanata Schlumberger, while M. bermudezi Drooger, M. thalmanni Drooger and M. panamensis (Cushman) are late Oligocene species restricted to the western hemisphere. M. gunteri Cole and M. tani Drooger are found in the Aquitanian on both sides of the Atlantic. Burdigalian beds are marked by M. irregularis (Michelotti) and M. intermedia Drooger both in America and in the Western Mediterranean area. The American species, M. bronnimanni Drogger, is thought to be yet another Burdigalian-Helvetian representative of the family. M. cushmani Vaughan occurs in Helvetian sediments on both sides of the Atlantic, but M. mexicana Nuttall seems to have been confined to the Helvetian of the western side. M. mexicana was the most advanced miogypsinid in the Gulf Coast and the last member of the family to become extinct here. Both nepionic acceleration and centripetal trends are repeatedly confirmed by the Gulf Coast data. Further study is needed on planktonic Foraminifera, but at present a late Helvetian age is logical for the ranges of Globigerinatella insueta Cushman and Stainforth, Globigerinoides bispherica Todd, and Globorotalia praemenardii Cushman and Stainforth. Orbulina and Globorotalia menardii (d'Orbigny) seem to have appeared contemporaneously in the Gulf Coast records; the beginning of Orbulina in Europe coincides with the Helvetian-Tortonian boundary, and the range of Globorotalia fohsi Cushman and Ellisor is mainly Tortonian. It is apparent that this new faunal evidence affords a better understanding of time relationships within the Gulf Coast, which can be extended to areas of tropical America. These fossils indicate that Suwannee limestone which is exposed at numerous Florida localities and fossiliferous carbonate rocks to which the name has also been applied in various Florida wells should be correlated in part with the Chickasawhay formation of Mississippi and in part with the subsurface Anahuac formation and the lower Fleming of Texas and Louisiana. The Tampa limestone of Florida is correlated with the lower middle Fleming. Some of the faunal zones of the Gulf Coast subsurface, such as the well known Heterostegina zone, are considered to be time-transgressive units.

All the most widely known methods described in the literature fall short of these requirements . In the "classical" method described by Be (1969a) and Boltovskoy (1966), the total • sample is inspected through a microscope and any foraminiferal tests visible are removed by a pipette or a brush. The method is time-consuming and inaccurate in that the worker is unconsciously selective towards larger and more conspicuous species such as the red Globigerinoides rubev or Hastigerina pelagiaa. Another source of biased error is the element of fatigue, which causes a decrease in operator accuracy through the working period. In the floatation method proposed by Be (1959b), a saturated NaCl solution is used to separate shelled from soft-bodied plankton. When placed in this solution in a settling tube, ideally the soft-bodied plankton remain floating while foraminifera, with the other shelled organisms, sink to the bottom. A major draw-back of this method is that spinose species are commonly entangled with the other soft-bodied plankton and remain floating. By the ignition method, proposed by Sachs et_ al^ (1964) samples are initially treated with hydrogen peroxide. After the excessive soft organic material is digested, the samples are ignited in a muffle furnace at 500°C. This treatment removes all organic material, leaving only skeletal matter. Both the initial treatment with the digestive and the final treatment in the furnace attacks the calcareous material to some extent. For example, the surfaces of the tests of foraminifera and pteropods is etched and most of the spines are removed in this process. In many instances it was found that samples had exploded in the furnace causing loss and contamination of the sample.

Twenty-nine Miocene planktonic foraminifera are listed from subsurface sediments of the coastal plain of the state of Rio Grande do Sul, southern Brazil. A tentative correlation with the boundary of the Globigerinatella insueta and Globorotalia fohsi barisanensis zones in the Caribbean sequence is proposed. Important for the stratigraphical comparison is the Globigerinoides bisphericus-Orbulina suturalis evolutionary lineage corresponding to the world-wide Orbulina surface.

"The lineages of Globigerina bulloides, Globigerina ampliapertura to G. apertura, Globigerinoides quadrilobatus to Orbulina, and Globorotalia fohsi are described as developed in the temperate southeastern Australian region. Comparison with tropic and northern temperate faunas demonstrates continuous temperate-climate optimum development for Globigerina bulloides and tropic for Globorotalia fohsi. The others were tolerant and allow reliable interprovincial stratigraphic correlation. Tertiary marine faunal provinces were distributed asymmetrically about the equator, probably by major ocean currents, as at present."

Environmental changes (glacial/interglacial cycles) reflected in G. rubra morphology, Quaternary

"In the region of the classic locality of Rosignano, the highly developed Lepidocyclina (Nephrolepidina) tournoueri is accompanied by Miogypsina (Miogypsina) globulina. The associated planktonics mainly consist of Globoquadrina dehiscens and Globigerina globularis, with scarcer Globigerinoides triloba. The Burdigalian age of this fauna shows the persistence of the Lepidocyclinidae in the Miocene of the Mediterranean area."

The genera "Sphaeroidinella" and "Sphaeroidinellopsis" are shown to be isomorphic growth forms derived from at least two different species of Globigerinoides in the bathyal zone. The Sphaeroidinella dehiscens datum, defining the approximate Miocene-Pliocene boundary, falls within the 8 to 10 million year interval in southern California. Isomorphism in "Sphaeroidinella" and "Sphaeroidinellopsis" ORVILLE L. BANDY, JAMES C. INGLE, JR., AND WILLIAM E. FRERICHS Allan Hancock Foundation and Department of Geology University of Southern California Los Angeles, California

The Plio-Pleistocene boundary has been located at the place where certain northern species of marine invertebrates first appear in the continuous Plio-Pleistocene sections of Italy. The section at Le Castella, near Crotone, southern Italy, consists of clays with diatomaceous layers and a few thin sand layers. The Plio-Pleistocene boundary there is clearly marked by the appearance of Anomalina baltica and other northern species of Foraminifera. Calabnan (lower Pleistocene) sediments 210m thick overlie the boundary, and upper Pliocene sediments 1405 m thick underlie it. The fossil fauna of the Plio-Pleistocene section consists essentially of abundant pelagic and benthonic Foraminifera, and diatoms. The benthonic microfauna indicates a depositional depth of about 500 m. There is no evidence of turbidity currents and submarine slumping. A section 167.80 m thick, including the paleontologically defined Plio-Pleistocene boundary, was logged and sampled at close stratigraphic intervals. Oxygen isotopic analyses of different species of pelagic and benthonic Foraminifera and of shell fragments of benthonic mollusks at successively higher stratigraphic positions in the section have revealed numerous temperature oscillations. Surface temperatures, probably representing summer averages, as indicated by Globigerinoides rubra and G. sacculifera, ranged from 21°C. to more than 30°C. in the late Pliocene, from 16°C. to more than 30°C. in the late Pliocene-early Pleistocene, and from 12° C. to 28° C. in the late Pleistocene. Temperatures at some depth and/or at a season other than the summer, as indicated by Globigerina bulloides and G. inflata, ranged from 20°C. to 28°C. in the late Pliocene, from 11°C. to 22°C. in the late Pliocene-early Pleistocene, and from 9°C. to 18°C. in the late Pleistocene. Temperatures given by benthonic Foraminifera ranged from 14°C. to 20°C. in the late Pliocene and from 11°C. to 22°C. in the late Pliocene-early Pleistocene (no data available for the late Pleistocene). Temperatures above 30°C. may be due, in part, to isotopic effects of the sea water. The above figures clearly indicate a major shift of the temperature ranges toward lower values from the late Pliocene to the late Pleistocene. No major temperature change seems to have occurred across the paleontologically defined Plio-Pleistocene boundary. Since the secular temperature minima of the late Pliocene are somewhat lower than present average summer temperature, an areal extension of the ice somewhat greater than that at present is suggested. Such extension probably increased at the times corresponding to the even lower temperature minima of the early Pleistocene. Major continental glaciations, however, may not have started until later, because none of the temperature minima in the section at Le Castella appear to have reached values as low as those obtaining during the glacial ages in the eastern Mediterranean. The temperature changes in the section at Le Castella are paralleled by important changes in the microfauna.

X-ray and spectrographic analyses of a number of species of Recent and Pleistocene pelagic foraminifera from Caribbean, Atlantic and Pacific deep-sea cores indicate that the tests are made of virtually pure calcite, with only about 0.11% of strontium. Mineralogical and chemical composition of the tests of certain pelagic foraminifera CESARE EMILIANI Institute for Nuclear Studies University of Chicago Chicago, Illinois Very little work has been done on the mineralogical and chemical composition of the tests of pelagic foraminifera. To the knowledge of the writer, only three X-ray analyses have been published. These show a calcitic structure for Globorotalia menardii (Mayer, 1932) and for Globigerinoides rubra and Globorotalia tumida (Switzer and Boucot, 1955). The few chemical analyses which have been published (Clarke and Wheeler, 1922; Revelle, 1944) show small amounts of Si, Al, Fe and Mg. Only the latter two may actually be contained in the calcite structure. The others may indicate sedimentary contamination, as it is impossible to wash specimens absolutely clean in preparation for analysis. At the suggestion of the writer, X-ray and spectrographic analyses were made on a number of species of pelagic foraminifera by Dr. J. R. Goldsmith and Mr. 0. Joensuu, respectively, of the Department of Geology, University of Chicago. The X-ray analyses followed a method for determining Mg in Ca positions in the calcite structure. Powder diffraction pictures were taken with North American Philips 114.19 mm. cameras using Fe radiation, as described by Goldsmith, Graf and Joensuu (1955). Back-reflections, highly sensitive to Mg content, were compared with a pure calcite standard. The spectrographic analyses were made with a 21-foot grating spectrograph (Jarrell-Ash Co.), using a technique which will be described elsewhere by Joensuu. These analyses are accurate to within ?+10% of the determined values. The foraminifera were obtained from deep-sea cores from the Caribbean Sea, the equatorial and North Atlantic Ocean, and the Pacific Ocean, kindly furnished by Professor H. Pettersson of the Oceanographic Institute of G6teborg, D. B. Ericson of the Lamont Geological Observatory, and Dr. G. Arrhenius of the Scripps Institution of Oceanography. The locations and depths of cores are given in Table 1. The pr fix "A" identifies the Lamont cores. Cores distinguished by "A" or "B" following the core number are short pilot cores intended to sample superficial sediments. The cores have been described by Arrhenius (1952), Ericson (1953), and Phleger, Parker and Peirson (1953). TABLE 1 LOCATIONS AND DEPTHS OF CORES Core No. A179-4 234A, 234 246A, 246 280A 58B, 58 Location 13036' N. 74048' W. 5045' N. 21043' W. 0?48' N. 31?28' W. 34057' N. 44016' W. 6?44' N. 129028' W. Depth (meters) 2965 3577 3210 4256 4440 Samples from the uppermost portions of the pilot cores and of core A179-4 are thought to represent essentially modern sediments, while the deeper samples represent Pleistocene sediments. Foraminifera belonging to different species were separated from each sample and crushed between glass slides, washed in distilled water in an agitator for one hour, and dried in an oven at 95? C. The results are listed in Table 2. Results of the X-ray analyses all indicate that the cell spacings are the same as those of virtually pure calcite. The presence of substituting cations was always beyond detectability (

The new subspecies Globigerina woodi connecta, here described from Otaian stage beds of north Auckland, New Zealand, evolved from G. woodi woodi populations in the lower part of the stage in New Zealand and in the G. woodi zone of southeast Australia at about the same time, and represents an intermediate link between G. woodi woodi and Globigerinoides trilobus.