CHAP. 34] THE PLEISTOCENE RECORD 895 



systematic study of it was made by Penck and Briickner (1909), who defined the 

 Wiirm glacial in the Alps. Those workers recognized within the Wiirm two 

 chief phases of glaciation, separated in time by an interval of deglaciation. 

 Subsequently, detailed study by F. Brandtner and others (and as yet mainly 

 unpublished) of the sequence of loess sheets and soil zones along the Danube 

 River in Lower Austria revealed a sequence confirming the concept of at least 

 two cold-climate units within the Wiirm succession in the Alps. The evidence 

 consists basically of three chief loess bodies, representing glacial times in the 

 nearby mountains, and two intervening soils representing times of Alpine 

 deglaciation. The sequence was calibrated in part through ^^C dating. Later it 

 was shown that the succession of end moraines and loess bodies in northern 

 Germany, related to the Scandinavian Ice Sheet, could be fitted to the Alpine- 

 Lower Austria scheme by similarity of events, although as yet the fit is confirmed 

 only in small part by i^C. An attempt to show the sequence in graphic form was 

 made by Woldstedt (1958, fig. 1). Although the curves for the last 27,000 years 

 B.P. are fairly well supported, the older part of the record is still very poorly 

 controlled by reliable data. Time calibration of the older part is discussed by 

 de Vries (1958, 1959), Haring et al. (1958), and Andersen et al. (1960). i4C dates 

 of a few samples from northern Germany, the Netherlands and Britain, taken 

 from positions in the lower part of the sequence and related to fossils that 

 indicate the climatic character at the time, give a reasonably consistent result, 

 although there are still large gaps. The oldest dated sample (de Vries, 1958, 

 GRO-1397) of Wiirm age has a date of 64,000 i^Q years, if a result equivalent 

 to more than 11 half-lives of i^C is accepted. This result would imply that the 

 end of the Riss-Wiirm interglacial occurred still earlier, an implication with 

 which the results reached by Rosholt et al. (1961, 1962) from a study of 

 deep-sea cores are compatible. 



The latest major glacial maximum appears to have occurred at around 

 18,000 years B.P. Thereafter warming and deglaciation occurred, with fluctua- 

 tions, of which the most notable were the temperature minimum at around 

 11,000 B.P., following ten or more centuries of markedly higher temperature 

 (Allerod time); and the Hypsithermal time of relatively high temperature 

 falling between about 9000 and 2600 years B.P. 



Much of the record of Wisconsin glaciation in central North America, 

 as recognized thus far, correlates with the later part of the European record, 

 embracing the last 25,000 years or so. The major glacial maximum, fixed in 

 Ohio at 18,000 years B.P. or somewhat later, the Allerod warmth, the post- 

 Allerod glacial readvance, and the Hy[3sithermal are all fairly well documented 

 and were essentially contemporary with the corresponding climatic fluctua- 

 tions in Europe. Events corresponding to the earlier part of the Wiirm sequence 

 in Europe, however, are less well known. Research between 1955 and 1962, 

 supported by i^c dates, has made possible a first approximation to a time- 

 calibrated sequence of such events in central North America, summarized by 

 Flint (1963), but alterations can be expected. Not only does the close similarity 

 between the events of the last 25,000 years or so on both sides of the Atlantic 



