E.— GEOGRAPHY 



"3 



and were made quite unwittingly by the primitive peoples concerned. 

 They would all be hunters, preying on wild animals or upon wild fruits 

 and grains. With the onset of any Ice Age, the forests, steppes, and 

 tundras move slowly but en masse to the south. A fall of temperature 

 of 12° F. is the maximum effect. This temperature range (by the ordinary 

 ratio explained in any text-book of climatology) ^ is normally equivalent 

 to a journey of some 800 miles toward the Pole. Such a migration of 

 vegetation would perhaps change half the Siberian forest into tundra, 

 and change the whole central Asiatic desert belt into steppe, while much 

 of the southern forest belt would gradually turn into desert. 



Research in Scandinavia has made it much easier for us to reconstruct 



Fig. 6. — Correlations of Climate and Culture, showing the Northward March of 

 the Ice-Cap, the Vegetation Zones and Primitive Man in Scandinavia since 

 the close of the Wurm Ice Age. The front of each diagram shows the Strata 

 in section. 



the movement of ice-caps, vegetation-zones, and of man himself (Griffith 

 Taylor 1934). De Geer and others working on the Varve-clays have 

 dated the moraine of the waning Wurm Ice Age as it developed in 

 South Sweden. They place it about 18,500 B.C. This is shown in Fig. 6, 

 at A, where Sweden is shown buried under the great ice-cap. Peat bogs 

 in North Germany and Denmark show that tundra plants were growing 

 south of the ice-cap at this time. Man had apparently not yet appeared 

 in Sweden. 



In block-diagram B (Fig. 6) we see that the ice-front has retreated 

 northward half-way along the Swedish Peninsula. This is dated about 

 9000 B.C. At that time the peat bogs in Germany show remains of 

 fir-trees, and here also we find the artefacts of Neolithic man. Apparently 

 Palaeolithic man found the tundra and steppe very unattractive and so 

 never settled on the Baltic. The next diagram C shows us a further 

 retreat during 5,000 years. The fir now covers Southern Scandinavia 



» Off China the world isotherms change 1° f. for about i degree of latitude. 



