Editing Key Largo (section)

==Geology and geography==
The island of Key Largo is an exposed, fossilized remnant of a coral reef formed during a period of higher sea level and then uncovered and eroded during a subsequent [[ice age]]. The highest elevation is a slight ridge forming the spine of the island, which rises to about {{convert|15|ft|m}}.

The island's [[Substrate (marine biology)|substrate]] is called [[Key Largo Limestone]]; in many places, [[fossil]]ized corals are visible at the surface.<ref>{{Cite web|url=https://mrdata.usgs.gov/geology/state/sgmc-unit.php?unit=FLPSk%3B0|title=Key Largo Limestone|url-status=live|archive-url=https://web.archive.org/web/20211128203338/https://mrdata.usgs.gov/geology/state/sgmc-unit.php?unit=FLPSk%3B0|archive-date=November 28, 2021|website=USGS|access-date=May 8, 2019}}</ref> Solution holes, which are pockets dissolved in the limestone by acidic rainwater, form shallow depressions in the land. The natural shoreline of the island is generally rocky. A slippery, gray, limestone-based clay called "[[marl]]" is the shoreline and near-shore soil. No natural sand beaches occur on the island. Inland, decomposed vegetation forms a rich, acidic humus soil up to about 6 in (15 cm) thick, topped by "[[leaf litter]]". The soil supports a diverse flora of herbaceous plants, woody shrubs, and hardwood trees.