the territory located between the Volga, the Urals, Severnye Uvaly, and the Caspian region.
The High Trans-Volga Region includes the Verkhniaia Kama (elevation to 337 m), Viatka Uval (to 284 m), Bugul’ma-Belebei (to 418 m), and Obshchii Syrt (to 405 m) uplands. The High Trans-Volga Region is composed of Permian rock: sandstones, shales, clays, marls, limestones, dolomites, and gypsum; on the south it is composed of Mesozoic clays and sands. The relief is characterized by erosion; the upper layer is formed by residual uplands, or shikhany, while the lower layers are erosion-stratified plains. There is much karst topography. The Low Trans-Volga Region occupies the low (elevation to 125–150 m) left bank of the Volga from Kazan to Kamyshin. It is a tectonic trough filled with Cenozoic sand and clay deposits of the ancient Caspian Sea. Along the Volga there is a line of terraces that gives way to a watershed plain in the east. The floodplain and part of the terraces are flooded with the waters of the Kuibyshev Reservoir. The Trans-Volga Region has a continental climate and forest, forest-steppe, and steppe landscapes. It is rich in petroleum.
V. K. ZHUCHKOVA