Geoscience Reference
In-Depth Information
Rocks rise from the sea near Gros Morne, Newfoundland, which has been called the “Galápagos of Geology.”
PLACODERM
Out of the Water
During this mountain-building period, life was evolving in the planet's waters and was about to take its first
tentative steps onto land. Diversity increased during the Silurian (443-418 million years ago) as a variety of
invertebrates, including brachiopods, clams, snails, sea lilies, bryozoans, and trilobites populated marine wa-
ters. During the Devonian (418-362 million years ago), new species of flora and fauna proliferated in the wa-
ter and on land. But it is rightly known as the Age of Fishes, because during the 56 million years of the Devo-
nian many new fish prototypes appeared. The best record of this proliferation of fish species is found in the
Miguasha cliffs at the mouth of the Restigouche River, which is now famous for its large Atlantic salmon. The
pioneering geologist Abraham Gesner, best known for inventing kerosene, first discovered the wealth of an-
