A recent human campsite, occupied in 1973 by members of the Dassanetch tribe of northern Kenya, was observed from its creation through its subsequent burial in flood events 4 months later. The site was excavated as an archeological occurrence in the summer of 1974. Analyses of field and laboratory data yield a detailed picture of sedimentary structures, bone transport and burial, and site preservation in a well-documented depositional situation. Trampling by site occupants was apparently instrumental in burying much small bone prior to the flood events which acted on the site. About 30 cm of sediments accumulated on the site during four or five flood events. Individual sedimentary beds can be related to specific observed flood events in the drainage system. The ultimate preservation of the site as part of the region's archeological record would depend upon the interaction of sediment deflation and the varying local water table. Specific conditions which tend to preserve human sites in water-poor environments may consistently select seasonally biased vestiges of human settlement and economy.

A Pleistocene drift sequence in hummocky terrain along part of the southern Avalon Peninsula of Newfoundland is interpreted to comprise complexly interrelated lodgement till, melt-out till, flow till, supraglacial and proglacial outwash, and supraglacial rhythmites. The gray and tan melt-out tills are stacked in imbricate fashion, giving rise to exceptionally thick stratigraphic sections. Contacts between melt-out tills are interpreted as remnants of shear planes because they are sharp, they dip in the up-ice direction, and they converge toward valley margins. Overlying flow tills interdigitate with supraglacial outwash. The drift sequence was deposited during a single episode of glaciation, rather than by repeated glacier advance, as previously proposed. It is the product of thrusting of englacial debris along ice-marginal shear planes, subsequent melting-out of englacial debris, and formation of supraglacial flow till and outwash. Preservation of this sequence probably is due to high content of englacial debris within the Wisconsinan ice. The sedimentary, glacitectonic, and morphologic features of this sequence are similar to those found at the margins of certain Arctic glaciers of subpolar thermal regime which have recently been the subject of Pleistocene glacial sedimentation models for west-central Canada and Great Britain. Recognition of these distinct elements indicates wisconsinan glacier lobes were of the cold Arctic type in southeastern Newfoundland. Alternative explanations for this sequence, such as deposition by glaciers of temperate thermal regime or by surging glaciers, are discounted. Because the features described here are complex and difficult to recognize, they may be more widespread in Pleistocene drift than has previously been interpreted.

Quaternary deposits on the Pacific slope of Washington range in age from the earliest known interglaciation, the Alderton, through the Holocene. Pollen stratigraphy of these deposits is represented by 12 major pollen zones and is ostensibly continuous through Zone 8 over more than 47,000 radiocarbon yr. Before this, the stratigraphy is discontinuous and the chronology less certain. Environments over the time span of the deposits are reconstructed by the comparison of fossil and modern pollen assemblages and the use of relevant meteorological data. The Alderton Interglaciation is characterized by forests of Douglas fir (Pseudotsuga menziesii), alder (Alnus), and fir (Abies). During the next younger interglaciation, the Puyallup, forests were mostly of pine, apparently lodgepole (Pinus contorta), except midway in the interval when fir, western hemlock (Tsuga heterophylla), and Douglas fir temporarily replaced much of the pine. Vegetation outside the limits of Salmon Springs ice (>47,00034,000 yr BP) varied chiefly between park tundra and forests of western hemlock, spruce (Picea), and pine. The Salmon Springs nonglacial interval at the type locality records early park tundra followed by forests of pine and of fir. During the Olympia Interglaciation (34,000–28,000 yr BP), pine invaded the Puget Lowland, whereas western hemlock and spruce became manifest on the Olympic Peninsula. Park tundra was widespread during the Fraser Glaciation (28,000–10,000 yr BP) with pine becoming more important from about 15,000 to 10,000 yr BP. Holocene vegetation consisted first of open communities of Douglas fir and alder; later, closed forests succeeded, formed principally of western hemlock on the Olympic Peninsula and of western hemlock and Douglas fir in the Puget Lowland. Over the length of the reconstructed environmental record, climate shifted between cool and humid or relatively warm, semihumid forest types and cold, relatively dry tundra or park tundra types. During times of glaciation, average July temperatures are estimated to have been at least 7°C lower than today. Only during the Alderton Interglaciation and during the Holocene were temperatures higher for protracted periods than at present.

Pollen preserved in a peat deposit from a large swamp, the Old Field in the Mississippi River Valley near Advance, Missouri, records radiocarbon-dated vegetation changes between 9000 and about 3000 years ago. The principal feature of both the percentage and influx pollen diagrams is the replacement of arboreal pollen, primarily Quercus, Fraxinus, and Cephalanthus, with Gramineae and NAP between 8700 and 5000 years BP. This vegetation shift is interpreted as reflecting a decrease in the extent of the Old Field swamp and its associated bottomland forest species along with the expansion of a grass-dominated herb community, as a result of a reduction in available ground water. The desiccation of the swamp during this period indicates a reduction in precipitation within the ground-water source area and a shift to a drier climate in the southern Midwest. The pollen suggests that the lowest water levels and driest climate in southeastern Missouri lasted from 8700 to 6500 years BP, at which time there is a partial reappearance of swamp species. Relatively dry conditions, however, continued until at least 5000 years BP. Although pollen influx data are lacking from the upper part of the profile, the relative pollen frequencies suggest an increase in trees after 5000 BP. The replacement of the arboreal vegetation by grasses and herbs between 8700 and 5000 years BP reflects the period of maximum expansion of the Prairie Peninsula in southeastern Missouri. The Old Field swamp provides the first pollen evidence that the vegetational changes along the southern border of the Prairie Peninsula were chronologically similar to those on the northern and northeastern margins.

In the equatorial Pacific, between the Galapagos Islands and the coast of South America, two kinds of upwelling of oceanic waters occur. One is related to coastal upwelling and the other to surfacing of the Equatorial Undercurrent. Both of those processes are associated with the development of the southeast trade winds blowing in this area. Coastal upwelling is increased when the trade winds are intensified, and the surfacing of the Equatorial Undercurrent occurs when the trades weaken. The development of coastal upwelling and the surfacing of the Equatorial Undercurrent are inferred from the radiolarian assemblages in the sediments. The abundance of quartz, opal, and radiolarian assemblages in the deep-sea sediments of this area, as well as the distance from the sample locations to land and to the quartz source, is correlated with the intensity of the trade winds (in February and August) through multiple regression analysis. The chronostratigraphy of core V19-29 (3°35′S, 83°56′W), used in this study, is inferred on basis of its δ180 record. During the last 75,000 years, the fluctuations in intensity of the trade winds have been concurrent with or preceded the fluctuations in the amount of ice stored on the continents. In general, the wind velocity of the winter trades has been intensified during cool climatic stages of the earth (δ180 stages 4 and 2) and they have been relaxed during warm stages (δ180 stages 3 and 1). Seasonal contrast of the trade winds has also fluctuated within time, having been relatively high during the upper part of δ180 stage 3.

Global atmospheric and oceanic circulation effects of expansion of continental ice sheets initiated upwelling in the western equatorial Pacific and simultaneously intensified upwelling in the eastern equatorial Pacific; contraction of the ice sheets reversed the process. Published Pleistocene paleoclimatic stratigraphies correlated across the entire equatorial Pacific exhibit eight such cycles in the Brünhes epoch. The extrapolated chronostratigraphies for the equatorial Pacific compare favorably with published paleoclimatic schemes for the southeastern, eastern, and northern Pacific Ocean. The Southern Ocean record exhibits fewer, and possibly also consistently older, climatic variations. A time progression or lack of synchrony of marine Pleistocene climatic events is not inconsistent with modified “Milankovitch” hypotheses, such as that involving Antarctic ice-sheet instability.

This paper documents and investigates an important source of inaccuracy when paleoecological equations calibrated on modern biological data are applied downcore: fossil assemblages for which there are no modern analogs. Algebraic experiments with five calibration techniques are used to evaluate the sensitivity of the methods with respect to no-analog conditions. The five techniques are: species regression; principal-components regression [e.g., Imbrie, J., and Kipp, N. G. (1971). In “The Late Cenozoic Ages,” 71–181]; distance-index regression [Hecht, A. D. (1973). Micropaleontology 19 , 68–77]; diversity-index regression (Williams, D. F., and Johnson, W. C. (1975). Quaternary Research 5 , 237–250]; weighted-average method [Jones, J. I. (1964). Unpublished Ph. D. Thesis, Univ. of Wisconsin]. The experiments indicate that the four regression techniques extrapolate under no-analog conditions, yielding erroneous estimates. The weighted-average technique, however, does not extrapolate under no-analog conditions and consequently is more accurate than the other techniques. Methods for recognizing no-analog conditions downcore are discussed, and ways to minimize inaccuracy are suggested. Using several equations based on different calibration techniques is recommended. Divergent estimates suggest that no-analog conditions occur and that estimates are unreliable. The value determined by the weighted-average technique, however, may well be the most accurate.