2006, Terri Farley, Phantom Stallion #21, p. 210Piece of cake? her mind screeched. Piece of ten-million-year-old permafrozen glacier, maybe.
2001, Graham Taylor and R.A. Eggleton, Regolith Geology and Geomorphology, p. 239Pingos form by the penetration of unfrozen but saturated sands to the surface through a layer of permafrozen ground.
1980, Robert Auty, Companion to Russian Studies: An Introduction to Russian History, p. 11With the very long winter, permafrozen soil, and low evaporation, the soil is waterlogged.
