Reseña del libro "Rivers in Rock: Elora Gorge Field Companion and Natural History (en Inglés)"
This richly illustrated book is botha visitor's guide to one of southwestern Ontario's most striking landforms -the Elora Gorge on the Upper Grand River - and a thorough, accessible introductionto its natural and recent human history. The book introduces rivers that flow inbedrock, between rock walls and through precipitous gorges, unlike the subduedterrain that the last Ice Age bequeathed most of southwestern Ontario. It then leadsthe visitor to three viewpoints on and three excursions through the gorge, witha wealth of information about its rocks, fossils, caves, cliffs, rockslides, rockfalls, floods and erosional processes. It takes the reader through five "ages"of the gorge. In the First Age the gorge bedrock originated as reef limestone430 million years ago in prehistoric tropical seas. The Second Age saw the gorge rocks make a great, 400-million-yearjourney from tropical seas to the heart of a continent via plate tectonics. Inthe Third Age, the retreating Laurentide Ice Sheet created conditions 17,000 to15,000 years ago in which ice lobes, glacial lakes and meltwater spillwaysinteracted to incise the gorge in an ice-free area known as the Ontario Island.In the Fourth Age the gorge, nestled in an immense forest, developed at aslower pace moderated by dense woods, fallen branches and beaver dams. In theFifth Age, the gorge entered the Anthropocene as European settlers came to disruptand dominate its development and unlock its secrets. Full of original photographs, maps anddiagrams, Rivers in Rock is an authoritative guide tothe Elora Gorge that will fascinate visitors and researchers alike.
