Geography in "The Mrem Go West"

As the Ice Age was ending, melting glaciers caused the Old Water to rise, surmounting the tops of the Quaxo Hills and spreading westward. The Hollow Lands were inundated by the New Water. Many sentient beings, Liskash and Mrem alike, were killed in the flood, while those insightful enough to see the signs were able to get out beforehand. On the south side of the New Water, the Warm Lands were dominated by Liskash. Mrem who lived there were slaves to Liskash, or lived in nomadic groups by vigilantly defying the "dinos."