Relatively complete stratigraphic records of the Bonneville cycle and of at least one and probably two earlier lacustrine are exposed along the Bear River below Cutler Dam in northern Utah between altitudes of 1290 and 1365 m. In most exposures the unconformity between the Bonneville Alloformation and the underlying unit, herein named the Cutler Dam Alloformation, is marked by slight erosional relief and by a weakly to moderately developed buried soil, herein named the Fielding Geosol. In truncated profiles, the Fielding Geosol reaches a maximum of stage II carbonate morphology. Wood from near the base of the Cutler Dam Alloformation yielded a 14C date of >36,000 yr B.P. (Beta-9845). Alloisoleucine/isoleucine (aIle/Ile) ratios of Sphaerium shells from the Cutler Dam beds average 0.15 ± 0.01 in the total hydrolysate, which is significantly greater than the average for Sphaerium shells of Bonneville age elsewhere in the basin. Therefore, the Cutler Dam Alloformation is older than 36,000 yr B.P., but much younger than deposits of the Little Valley lake cycle (140,000 yr B.P.?) which bear shells having significantly higher aIle/Ile ratios. The Cutler Dam Alloformation along the Bear River may be broadly correlative with marine oxygen-isotope stages 4 or 3. Fine-grained, fossiliferous, marginal-lacustrine facies of the Cutler Dam Alloformation are exposed at altitudes near 1340 m, and are probably the highest exposures of sediments deposited in the early or middle Wisconsin lake in the Bonneville basin.

Middle Park, a high‐altitude basin in the Southern Rocky Mountains of north‐central Colorado, contains at least 59 known Paleoindian localities. At Barger Gulch Locality B, an extensive Folsom assemblage (˜10,500 14C yr B.P.) occurs within a buried soil. Radiocarbon ages of charcoal and soil organic matter, as well as stratigraphic positions of artifacts, indicate the soil is a composite of a truncated, latest‐Pleistocene soil and a younger mollic epipedon formed between ˜6000 and 5200 14C yr B.P. and partially welded onto the older soil following erosion and truncation. Radiocarbon ages from an alluvial terrace adjacent to the excavation area indicate that erosion followed by aggradation occurred between ˜10,200 and 9700 14C yr B.P., and that the erosion is likely related to truncation of the latest‐Pleistocene soil. Erosion along the main axis of Barger Gulch occurring between ˜10,000 and 9700 14C yr B.P. was followed by rapid aggradation between ˜9700 and 9550 14C yr B.P., which, along with the erosion at Locality B, coincides with the abrupt onset of monsoonal precipitation following cooling in the region ˜11,000–10,000 14C yr B.P. during the Younger Dryas oscillation. Buried soils dated between ˜9500 and 8000 14C yr B.P. indicate relative landscape stability and soil formation throughout Middle Park. Morphological characteristics displayed by early Holocene soils suggest pedogenesis under parkland vegetation in areas currently characterized by sagebrush steppe. The expansion of forest cover into lower elevations during the early Holocene may have resulted in lower productivity in regards to mammalian fauna, and may partly explain the abundance of early Paleoindian sites (˜11,000–10,000 14C yr B.P., 76%) relative to late Paleoindian sites (˜10,000–8000 14C yr B.P., 24%) documented in Middle Park. © 2005 Wiley Periodicals, Inc.

Haploborolls and Ustifluvents with A‐C horizonation characterize Holocene soil development in alluvium and colluvium of the Laddie Creek valley. Cumulic soils with overthickened A horizons, including those of Altithermal age, have formed along the valley walls under the influence of spring activity from the Amsden Formation (Mississippian‐Pennsylvanian). Soil texture, mineralogy, and to some extent color, are inherited largely from sediment derived from the Amsden and Tensleep (Pennsylvanian) Formations. The valley was able to support human occupation during Altithermal time (ca. 7500‐4000 B.P.) because of springs emanating from the valley walls. Past spring locations are identified from soil morphology and stratigraphy. Springs are still active along the valley, although they have shifted positions many times in the past. The association of spring soils with Altithermal‐age occupation at the site (ca. 6600‐5700 B.P.) does not coincide with the caliche concept of the Altithermal paleosol in Holocene alluvial valleys in Wyoming basins as identified by Leopold and Miller. Nevertheless, early man of Altithermal time probably sought higher elevations within mountains of the region where springs offered water and the environs provided food and shelter—thus enabling human groups to survive the drought, and possible high temperatures, which seemingly prevailed in the basins and plains.

Bryan and Albritton (1943) were among the first to demonstrate the use of soil morphology, genesis, and stratigraphy in interpretation of archaeological sites for purposes of understanding climatic change and conditions at time of site occupation. This was an outgrowth of Bryan's pioneering work in studies at the Lindenmeier site (Fig. 1) in Colorado (Bryan and Ray, 1940) and cave sites, such as Sandia and Ventana Caves in New Mexico and Arizona (Bryan, 1941a, 1950). Judson (1953) did similar work at the San Jon site in New Mexico as did Hack (1942) in the Hopi Buttes area of Arizona. At the Horner site (Fig. 1) in Wyoming (Jepsen, 1953; Frison and Todd, 1987), Judson (1950) and Schullinger (1951) interpreted conditions based on stratigraphy, and Moss (1951) and Hack (1943) duplicated this at the Finley site (Fig. 1), also in Wyoming, while giving attention to soil morphology and climatic interpretation. Leopold and Miller (1954) recognized the recurrence of an Altithermal caliche or paleosol in alluvial sediments in Wyoming. Similar to Bryan (1941b), Haynes recognized soils in sediments throughout the West and Southwest, concluding that there was regularity in stream cutting and filling. In Wyoming, Haynes and Grey (1965) correlated events at the Sister's Hill site (Fig. 1) with the Leopold and Miller (1954) model and with patterns recognized elsewhere, especially in Arizona (Haynes, 1968). Later, Irwin-Williams and others (1973) identified a calcareous pedogenic unit at the Hell Gap site (Fig. 1) in Wyoming, and Benedict (1973, 1981,1985) and Benedict and Olson

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