In 1907, remnants of a mammoth and a woolly rhinoceros were discovered in the Pleistocene clays of an earth-wax mine in Starunia village. Then, in 1929, a nearly fully preserved woolly rhinoceros was found in the same mine. The unique combination of clays, oil, and brine into which the animals had sunk is responsible for their almost perfect preservation. During the late Pleistocene winters, when the ice and snow cover was present in the tundra “paleoswamp,” areas of inflow of brines, oils, and hydrocarbon gases had a higher temperature, which resulted in melting and cracking of the cover, and large mammals could be trapped. Geoelectric measurements, as well as molecular and stable isotope analyses of gases in the near-surface zone within the “paleoswamp” performed in 2004–2005, reveal a few places favorable to the burial and preservation of Pleistocene vertebrates.