The form of the plain, with the consequent possibility of ingress of westerly winds eastwards along the plain in summer, i.e. when the cold anticyclone has gone, gives a wedge of summer rain, alternating with considerable warmth, and this wedge is of the utmost importance in human geography. It is the area in which the summer green and winter black and white forest can grow, but as already stated the beech grows only in its western portion, and stops along a line from about Danzig or Königsberg to the east of Bukovina. Farther east the wedge is occupied by oak and elm, but the valuable beech is absent. The deciduous forest region includes South-west Finland, and its northern boundary runs eastward from the vicinity of Petrograd past Vologda. In many current maps its southern boundary is made much too sharp; the possibility of its growth depends here largely upon moisture, so it spreads into the drier south-east along river and other lines of relative dampness. The country with zones of deciduous forest interspersed with grass land is known as the 'Ukraine' or 'Border', and on its border towards the grasslands and semi-desert we have the Cossack country, with the Don Cossacks on the western side of the barren patches near the lower Volga, and the Orenburg Cossacks on their eastern side. The Ukraine and its eastern extensions are floored to a large extent with earth rich in organic matter (black earth, Tchernoziom), and have possibilities of considerable agricultural development if a settled scheme of life can be devised. In the south-west the language of the peasantry is Ruthenian, farther east Russian, both variants of Slavonic speech, but variants which seem fated to diverge from one another more and more. The climate of the Russian plain largely inhibits the higher grades of intellectual activity during the seasons of severe {68} cold and heat, with the result that those whose circumstances do not give them artificial protection from the weather must depend to a large extent on routine for the continuance of social organization. Conditions are thus not favourable for development of a complex unity over a wide area, and localism is therefore the prevailing tendency, carrying with it probabilities of maintenance and even of development of dialect-differences rather than of linguistic unification. These brief indications give us an insight into some of the more serious, if less appreciated, problems of governmental schemes in the varied vegetative regions of what was once Russia, which yet lacks convenient orographical boundary lines between its different parts.