Monroe County is a county in the state of Florida. As of the 2020 census, the population was 82,874. Its county seat is Key West. Monroe County includes the islands of the Florida Keys and comprises the Key West Micropolitan Statistical Area. Over 99.9% of the county's population lives on the Florida Keys. The mainland, which is part of the Everglades, comprises 87% of the county's land area and is virtually uninhabited with only 17 people in total.
A screw-pile lighthouse is a lighthouse which stands on piles that are screwed into sandy or muddy sea or river bottoms. The first screw-pile lighthouse to begin construction was built by the blind Irish engineer Alexander Mitchell. Construction began in 1838 at the mouth of the Thames and was known as the Maplin Sands lighthouse, and first lit in 1841. However, though its construction began later, the Wyre Light in Fleetwood, Lancashire, was the first to be lit.
Biscayne National Park is an American national park located south of Miami, Florida in Miami-Dade County. The park preserves Biscayne Bay and its offshore barrier reefs. Ninety-five percent of the park is water, and the shore of the bay is the location of an extensive mangrove forest. The park covers 172,971 acres and includes Elliott Key, the park's largest island and northernmost of the true Florida Keys, formed from fossilized coral reef. The islands farther north in the park are transitional islands of coral and sand. The offshore portion of the park includes the northernmost region of the Florida Reef, one of the largest coral reefs in the world.
The Florida Keys are a coral cay archipelago located off the southern coast of Florida, forming the southernmost part of the continental United States. They begin at the southeastern coast of the Florida peninsula, about 15 miles (24 km) south of Miami, and extend in a gentle arc south-southwest and then westward to Key West, the westernmost of the inhabited islands, and on to the uninhabited Dry Tortugas. The islands lie along the Florida Straits, dividing the Atlantic Ocean to the east from the Gulf of Mexico to the northwest, and defining one edge of Florida Bay. At the nearest point, the southern part of Key West is just 93 miles (150 km) from Cuba. The Florida Keys are between about 24.3 and 25.5 degrees North latitude.
Key Largo is an island in the upper Florida Keys archipelago and is the largest section of the keys, at 33 miles (53 km) long. It is one of the northernmost of the Florida Keys in Monroe County, and the northernmost of the keys connected by U.S. Highway 1. Three census-designated places are on the island of Key Largo: North Key Largo, near the Card Sound Bridge, Key Largo, eight to nine miles from the southern end of the island, and Tavernier, at the southern end of the island. As of 2010, the three places have a combined population of 13,850. None of Key Largo is an incorporated municipality, so it is governed at the local level by Monroe County.
Biscayne Bay is a lagoon with characteristics of an estuary located on the Atlantic coast of South Florida. The northern end of the lagoon is surrounded by the densely developed heart of the Miami metropolitan area while the southern end is largely undeveloped with a large portion of the lagoon included in Biscayne National Park.
Dry Tortugas National Park is a national park located about 68 miles (109 km) west of Key West in the Gulf of Mexico. The park preserves Fort Jefferson and the seven Dry Tortugas islands, the westernmost and most isolated of the Florida Keys. The archipelago's coral reefs are the least disturbed of the Florida Keys reefs.
The Delaware Basin is a geologic depositional and structural basin in West Texas and southern New Mexico, famous for holding large oil fields and for a fossilized reef exposed at the surface. Guadalupe Mountains National Park and Carlsbad Caverns National Park protect part of the basin. It is part of the larger Permian Basin, itself contained within the Mid-Continent oil province.
John Pennekamp Coral Reef State Park is a Florida State Park located on Key Largo in Florida. It includes approximately 70 nautical square miles (240 km²) of adjacent Atlantic Ocean waters. The park is approximately 25 miles in length and extends 3 miles into the Atlantic Ocean. It was the first underwater park in the United States. The park was added to the National Register of Historic Places on April 14, 1972. The primary attractions of the park are the coral reefs and their associated marine life.
Coral rag is a rubbly limestone composed of ancient coral reef material. The term also refers to the building blocks quarried from these strata, which are an important local building material in areas such as the coast of East Africa and the southeastern United States littoral.
Bahia Honda is an island in the lower Florida Keys.
Soldier Key is an island in Biscayne National Park in Miami-Dade County, Florida. It is located between Biscayne Bay and the Atlantic Ocean, about three miles north of the Ragged Keys, five miles south of Cape Florida on Key Biscayne, seven-and-a-half miles east of the mainland and three miles west of Fowey Rocks. It lies on the Safety Valve, a sand bar that separates Biscayne Bay from the Atlantic Ocean and moderates storm surges into the bay.
The Bahia Honda Rail Bridge is a derelict railroad bridge in the lower Florida Keys connecting Bahia Honda Key with Spanish Harbor Key. It was originally part of the Overseas Railway, but the state of Florida purchased it from the Florida East Coast Railway (FEC) after the 1935 Labor Day Hurricane and converted it for automobile use as part of the Overseas Highway in 1938. After a replacement Bahia Honda Bridge was opened in 1972, two spans of the old bridge were removed for the safety of boat traffic and to prevent pedestrian access to unsafe parts of the bridge.
Soldiers' Home Reef, also known as Rocky Point, National Military Asylum Reef, or Veterans' Hill is a fossilized coral reef rock formation in Milwaukee, Wisconsin. The reef formation was discovered by geologist Increase A. Lapham in the 1830s. It and other fossilized coral reefs that he discovered were the first geological reef formations described in North America, and are among the first described in the world. This reef was declared a National Historic Landmark in 1993.
The Florida Reef is the only living coral barrier reef in the continental United States. It is the third largest coral barrier reef system in the world. It lies a few miles seaward of the Florida Keys, is about 4 miles wide and extends 270 km (170 mi) from Fowey Rocks just east of Soldier Key to just south of the Marquesas Keys. The barrier reef tract forms a great arc, concentric with the Florida Keys, with the northern end, in Biscayne National Park, oriented north-south and the western end, south of the Marquesas Keys, oriented east-west. The rest of the reef outside Biscayne National Park lies within John Pennekamp Coral Reef State Park and the Florida Keys National Marine Sanctuary. Isolated coral patch reefs occur northward from Biscayne National Park as far north as Stuart, in Martin County. Coral reefs are also found in Dry Tortugas National Park west of the Marquesas Keys. There are more than 6,000 individual reefs in the system. The reefs are 5,000 to 7,000 years old, having developed since sea levels rose following the Wisconsinan glaciation.
Orange Island is the earliest emergent landmass of Florida dating from the middle Rupelian ~33.9—28.4 Ma. geologic stage of the Early Oligocene epoch and named for Orange County, Florida, United States of America.
The Traverse Group is a geologic group in Michigan, comprising middle Devonian limestones with calcareous shale components. Its marine fossils notably include Michigan's state stone, the Petoskey stone, among other corals and records of ancient marine life. A range of trilobites has also been found in the Traverse Group.
The Miami Limestone, originally called Miami Oolite, is a geologic formation of limestone in southeastern Florida.
The Ponce Limestone is a geologic formation in Puerto Rico. It preserves fossils dating back to the Neogene period (20.45 million years ago.
The geology of Guam formed as a result of mafic, felsic and intermediate composition volcanic rocks erupting below the ocean, building up the base of the island in the Eocene, between 33.9 and 56 million years ago. The island emerged above the water in the Eocene, although the volcanic crater collapsed. A second volcanic crater formed on the south of the island in the Oligocene and Miocene. In the shallow water, numerous limestone formations took shape, with thick alternating layers of volcanic material. The second crater collapsed and Guam went through a period in which it was almost entirely submerged, resembling a swampy atoll, until structural deformation slowly uplifted different parts of the island to their present topography. The process of uplift led to widespread erosion and clay formation, as well as the deposition of different types of limestone, reflecting different water depths.
Florida 
United States 
