In its long and rocky past, the place we call Ontario has traveled across the equator, been peppered and pockmarked by meteorites, seen the rise and decline of towering mountains, and gave rise to some very strange and now extinct organisms. In fact, what seems like a changeless landscape was once covered by vast seas and huge, continent-wide ice sheets which measured 2 kilometres thick, leaving in their wake, the Great Lakes. Ontario Rocks tells this fascinating 3 billion year long story of Ontario's geological evolution, from its beginnings as part of an early landmass called Arctica, its incorporation into enormous supercontinents, through to the repeated ice ages and abrupt climatic changes of the last few thousand years. Merging Canadian geology with global evolution, this highly illustrated survey also touches on the development of Ontario's mining and oil industries, and the commercial use of rocks as building material. Ontario Rocks concludes with an exploration of the "artificial" urban landscape, and how geologists use their knowledge to safeguard groundwater and rivers, dispose of wastes and understand the hazards posed by earthquakes and erosion. Ontario Rocks is a highly accessible sourcebook, perfect for students and all those intrigued by the history and formation of the land under us.