| San Juan Formation Stratigraphic range: Lutetian | |
|---|---|
| Type | Formation |
| Unit of | La Esperanza Group |
| Lithology | |
| Primary | Limestone |
| Location | |
| Coordinates | 16°42′N93°06′W / 16.7°N 93.1°W Coordinates: 16°42′N93°06′W / 16.7°N 93.1°W |
| Approximate paleocoordinates | 18°30′N83°48′W / 18.5°N 83.8°W |
| Region | Chiapas |
| Country |  |
The San Juan Formation is a geologic formation in Mexico. It preserves fossil corals dating back to the Lutetian stage of the Paleogene period. [1]
Mexico, officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatemala, Belize, and the Caribbean Sea; and to the east by the Gulf of Mexico. Covering almost 2,000,000 square kilometres (770,000 sq mi), the nation is the fifth largest country in the Americas by total area and the 13th largest independent state in the world. With an estimated population of over 120 million people, the country is the eleventh most populous state and the most populous Spanish-speaking state in the world, while being the second most populous nation in Latin America after Brazil. Mexico is a federation comprising 31 states and Mexico City, a special federal entity that is also the capital city and its most populous city. Other metropolises in the state include Guadalajara, Monterrey, Puebla, Toluca, Tijuana and León.
A fossil is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood, oil, coal, and DNA remnants. The totality of fossils is known as the fossil record.
Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically live in compact colonies of many identical individual polyps. Corals species include the important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton.
