Karymshina is a volcanic caldera. There is little to see on the ground since due to the volcano's great age (1.2-1.5 Million years), it has been eroded and covered by younger lava flows from other volcanoes. The caldera measures about 25 km x 15 km. The highest point is Mount Tolstyi at 1300m. In the Northwest of the caldera, there is an uplifted block, indicating an abortive eruption since forming. At present, the caldera floor is dry, but in the past it contained a lake that has left a sandstone layer. There are thermal springs, apparently heated by a large magma chamber that is still warm.