Paleontology and geologySilurian rocks in the Northeastern Region of Mexico were deposited in shallow to deep seas off the coast of Gondwana. These limestones, sandstones, and shales contain fossils of the many animals that lived in these seas, including brachiopods, gastropods, bryozoans, echinoderms, corals, and trilobites. At this time, the region was closer to portions of what would become Europe and South America than to North America so the fossils are more similar to those found in Europe and South America today. These deposits were brought to their present position by the motion and collision of tectonic plates. Over time, many of these rocks have been altered, buried below younger rocks, or eroded away. The exposures of Silurian rocks are too small to appear on this map, but other more detailed maps may show them. |