254 climate and geography: Europe Valuable information both for studying ancient climate and for dating comes from tree rings Ancient timbers and old trees dredged from rivers or preserved in waterlogged sediments can be sampled to examine their growth rings Thin rings indicate poor growing conditions, most often correlated with low rainfall and summer temperatures, while thick rings appear when the growing conditions are good Patterns of thick and thin rings can be matched from one timber to another, and regional sequences of growth rings can be built up Scientists have been able to develop over much of temperate Europe tree-ring sequences that cover thousands of years Dates obtained from tree rings are often to an exact year or even season For example, all the timbers used in a Bronze Age ceremonial monument on the coast of eastern England popularly known as “Seahenge” were cut in 2049 b.c.e., probably in the spring or early summer These are only a few of the techniques used for reconstructing the prehistoric environment Recently ice cores from Greenland have provided important evidence that bears on the environment of ancient Europe Land snails in ancient soils can show whether the landscape was forested or open Computer modeling of ancient climates has revealed potential periods of increased rainfall and winds THE END OF THE I CE AGE The environment and geography of ancient Europe are very much the product of the ice age, known as the Pleistocene Even in areas that were not covered by ice, the presence of the ice sheets and the tundra and other periglacial conditions that extended in front of them influenced almost every corner of the continent For example, the loess that fi lls the basins in the hills of central Europe and covers vast parts of the Carpathian Basin was deposited by winds sweeping up soils on the desolate unvegetated parts of western Europe and dropping it hundreds of kilometers to the east Even Mediterranean Europe felt the presence of the ice in the form of colder temperatures and lower sea levels The ice sheets advanced and retreated many times over the course of the Pleistocene Four major advances and retreats were punctuated by many minor ones Although humans have inhabited parts of Europe since at least 700,000 b.c.e., this discussion traces the environmental changes during the fi nal millennia of the Pleistocene and during the Holocene, the period of modern conditions during which we live today Around 17,000 b.c.e the large ice sheet that had covered northern and parts of central Europe for thousands of years began to retreat from its maximum advance The ice front ran in a line southeast from the North Sea across Denmark and northern Germany, reaching its southernmost point in southwestern Poland and then northeast across Belarus and Russia Smaller glaciers were found in the Alps and in the Scottish Highlands The ice retreated in fits and spurts, leaving debris and moraines in its wake across northern Europe Except for mountain glaciers in northern Scandinavia, the Ax made from reindeer antler found at Earls Barton, Northamptonshire, England, dating to about 8,500 b.c.e and characteristic of similar items from Denmark, the Netherlands, and Germany; this is one of several finds that links Britain to Europe at the very end of the last ice age, when sea levels were still low and there was dry land between Britain and Europe (© The Trustees of the British Museum)