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A faunal list of 362 sub-fossil Coleoptera obtained from 33 published and 24 unpublished sites of Pleistocene age in Canada and the neighbouring United States is given. A table indicates the distribution of families, with the number of species encountered, through discrete intervals of Pleistocene time. Seven species representing members of the Carabidae, Hydrophilidae, Staphylinidae, and Scolytidae have been used to illustrate distribution changes through the last interglacial/glacial/present interglacial cycle. The maximum distance so far recorded is a shift of over 9000 km for Anotylus gibbulus (Epp.), a staphylinid, found fossil in Toronto during the last interglacial, and today recorded only from Eurasia and Asia. A number of other species whose modern ranges are confined to northwestern North America have been found fossil in the Great Lakes – St. Lawrence region, over 4000 km distant. A similar shift is noted in species which today are found only in the eastern Canadian Arctic. Aspects of ice build up, marginal conditions outside the Laurentide Ice Sheet limits, Pleistocene climates, paleoecology, and sub-fossil insect localities are used to formulate hypotheses about three refugia around the perimeter of the Late Wisconsinan ice.

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The oxygen-isotope content of terrestrial plant cellulose is related to that of the source waters by a two-step process involving evapotranspirative leaf-water enrichment and equilibrium isotopic exchange between leaf water and atmospheric carbon dioxide. A combination of two models that describe these steps yields consistent agreement between measured and predicted climatic and isotopic data. Humidity is the dominant influence on variations in the cellulose 18O enrichment relative to the source water. A good first-order approximation of the average daytime relative humidity during the growth season at a site can be based on the linear correlation that exists between humidity and cellulose enrichment, without explicit consideration of factors such as temperature, δ18O of atmospheric vapour, and leaf boundary-layer dynamics.The value of the combined model for paleoclimatic reconstruction has been tested using fossil wood from a late glacial site at Brampton, Ontario. Estimates of the past relative humidity were derived from the divergence between measured δ18O values of fossil wood cellulose and environmental water isotopic compositions inferred from the carbon-bound deuterium contents of the cellulose. Growing conditions were apparently substantially drier than those at present between about 11 500 and 8700 years BP, at a time when coniferous forests predominated in southwestern Ontario. A shift in the inferred meteoric water composition over this period suggests a gradual increase in mean annual temperature of about 2 or 3 °C, in agreement with estimates of temperature change based on paleoentomological data.