Europe. The much more intensive tectonic disturbances of the Ukrainian region have produced a greater variety of plateau and plain country here than in White, Great or North Russia. The Ukrainian plateaus attain the contour-lines of 400 and even 500 meters and reveal precipices of tectonic origin, which for a long time were considered proof of Baer's law and have recently been explained as Davis Cuestas. The extensive working out of valleys in the Ukrainian plateau regions, the characteristic canon-like type of the valleys, the frequent occurrence of hills formed by erosion, lack of glacial formations and deposits, but evidences of great erosive and flattening action — these are the chief elements of difference between the plateau lands of the Ukraine and other Eastern European plateau lands. The plains of the Ukraine possess similarities to neighboring Central Europe only in the Northwest. Beyond this, they are all more or less decided steppes, the like of which are not met with in Central Europe, Hungary not excepted. At the same time the character of the steppes of the Ukraine is different from that of the steppe-region of Eastern Russia as well, chiefly because of the detail of the country and the peculiarities of vegetation, which are occasioned by differences of climate.
Hydrographically the Ukraine is distinguished by a web of rivers concentrating in the Pontus. The Ukraine embraces the river systems of the Dniester, Boh, Dnieper, Don and Kuban — not entirely, to be sure, yet by far the greater part, leaving only the sources of the two greatest rivers to the White and Great Russians. Only the most western borderlands of the Ukraine lie within the watersheds of the Baltic Rivers (the Vistula district); only the most eastern mountain-spurs in the water-shed of the Caspian Sea (Terek and Kuma). We may therefore, without hesitation, conceive of the Ukraine hydrographically as the northern part of the Eastern European water-shed.
In respect to climate, the Ukraine occupies an independent position in Eastern Europe. In fact, de Martonne recently declared "the Ukrainian climate to be one of the main types of climate of the earth." We shall not go so far as this, but we must emphasize the fact that the climate of the Ukraine differs no less from that of Poland, White Russia and Great Russia than does Germany's climate from that of England or France. An important wind-partition crosses the Ukraine in winter from East to West, subjecting the entire southern part to the sway of the east wind. Winter in the Ukraine is strictly continental, with a coldness of 30 degrees, but not with the semi-polar character of the Russian or the Central European character of the Polish winter. The east and southeast winds by day prevent the snow-blankets, produced by the moist south winds of the Pontus, from ever becoming too heavy, especially in the Southern Ukraine, and cause them to disappear quickly in the spring. In the spring the temperature rises very rapidly. The summer of the Ukraine is the hot continental summer, and despite the predominant Atlantic west winds and the abundant precipitation, it is not sultry. Autumn is pleasant and dry.
The climate of the Ukraine, then, is the continental climate of the Pontus. Toward the west it merges into the Central European climatic zone at the border of Poland, into the Eastern European continental climate at the border of White and Great Russia, into the Aralo-Caspian dry climate at the eastern border. The southern borderlands of the Ukraine, like those of France, constitute a transition to the Mediterranean climate.
In respect to its flora, the unique position of the Ukraine depends upon the fact that it embraces almost the entire region of the prairie-steppes of the Pontus, with their regions of transition to the Northern and Central European forest zone. Right east of the Don begin the steppes and desert-steppes of the Caspian region. Consequently, the Ukraine is the only country in Europe which has the prevailing character of the steppes. Here, again, this circumstance is of geographical importance and makes the Ukraine, in this respect also, a geographic unit.
The most important signs of independence as a geographic unit, however, are imparted to the Ukraine by its anthropogeographical conditions, to which we shall turn our attention in Book II of this little work.