The Volhynian Plateau extends over a broad space between the Buh in the west and the Teterev in the east, between the swampy plain of the Polissye in the north and the Dniester-Dnieper watershed and the upper Boh valley in the south. The Volhynian Plateau does not [47]possess the compactness of the Podolian or Rostoche Plateau. The swampy lowland of the Polissye extends along the rivers into the heart of Volhynia, thereby dividing its plateau country into several sections of different size. Likewise, the inner structure and geological constitution of Volhynia is variable. Western Volhynia, situated between the Buh and Horin Rivers, has a sub-layer of chalk marl, which is capped in places by layers of clay and sandstone and limestone of recent tertiary date. Eastern Volhynia lies entirely in the region of the primeval Ukrainian Horst, whose plicate granite-gneiss sub-layer is covered by old tertiary deposits. In this tectonically disturbed region we meet with traces of early volcanic action. Near Berestovetz, Horoshki, etc., species of eruptive rock appear as signs of radical disturbances of the earth’s surface. The surface soil of Volhynia is black soil only in the south. Beyond that we find here sandy soil, white earth and loamy soil, as signs of a one-time glacial covering and the action of fluvio-glacial waters. Many regions of loamy ground are rich in vegetable soil and not without considerable fertility. The lowest part of the Volhynian Plateau is the western part, which lies between the broad, marshy, flat valleys of the Buh and the Stir. The slightly undulating, almost level plateau surface, which declines imperceptibly toward the Polissye, here just attains a height of 200 m., while the next section, between the Stir and the Horin is the highest part of Volhynia. As an extension of the above-mentioned northern edge of Podolia, the Kremianetz-Ostroh hill-country intrudes between the two rivers. Over 400 m. high, near the city of Kremianetz, it declines toward the north, a steep section torn by gorges and ravines. Near Dubno, the plateau is cut into a picturesque hill country with a maximum height of 340 m. The hills of Volhynia have steep, often rocky declines and flattened rocky peaks. [48]North of Rivne and Lutzk they finally begin to be lower and more rounded, then they dwindle to a flat billowy tract of land, until, at the borders of the Polissye, we see only an almost perfect plain. Between the Horin and Sluch Rivers, the Volhynian Plateau becomes more uniform. Its surface is flat, and broad valleys of the rivers which flow toward the east, forming numerous ponds, part it slightly. Only in the south is a height of more than 300 m. reached; in the north, where the granite sub-layer appears everywhere, especially in river valleys, barely 200 m.