Ontario Rocks: Three Billion Years of Environmental Change

Dr. Patrick W. Colgan is Director of Research and Natural Lands at the
Royal Botanical Gardens.

Nick Eyles, a professor of geology at the University of Toronto, has
produced a splendid book about rocks and understanding life in Ontario
through geology. The volume begins at a high level, with a consideration
of uniformatarianism, geological time, and ecoregions. A chronology of
geology helpfully runs from Copernicus to contemporary continental
drift. Processes such as folding, earthquakes, and volcanoes are
presented.

An examination of the recycling of rocks, mineralolgy, and crystals is
followed by discussions of the problems and methods of stratigraphy. A
series of chapters covers geological eras to the present, with
explanations of dominant features of Ontario such as the Canadian Shield
and the Niagara Escarpment. Along the way, the reader encounters
fossils, petroglyphs, glaciers, salt mines, and incidents from Ontario
history. The implications of Ontario’s geology for its physical
landscape, economic bases, social structure, and artistic styles are
clearly articulated.

Amid the rich photographs, diagrams, and “Did you know?” boxes, the
exuberant and good-humored (e.g., “weathering heights”) text almost
disappears at times. Many technical terms are slipped in painlessly, and
a glossary gathers them together. The imaginary conversations with major
Canadian geologists are an engaging way of presenting role models.
Linking geological events with locations in Ontario literally brings the
message home, while photographs from elsewhere are used as needed.
Ontario’s geology is cleverly used to provide perspectives on diverse
topics, including art forms, geographical consequences, conservation
issues, and outdoor leisure, thereby linking humans to their
environment.

The large format is effectively used, but, for use in the field or
while touring stony buildings, it is a pity that there is no detachable
pocket guide.