• Ice ages are long periods of time during which the planet's surface is covered in ice..
• Glacialized rocks, drumlins, and till are the result of advancing glacial ice.
• Eskers, giant's cauldrons, kettles, and ridges are the result of retreating and melting glacial ice. 
• Key words: ice age, the Quarternary glaciation, till, drumlin, glacialized rock, erratic boulder, kettle lake, esker, ridge, giant's cauldron, clay.