The Avon Park Formation is a Middle Eocene geologic formation

Geologic formation

A formation or geological formation is the fundamental unit of lithostratigraphy. A formation consists of a certain number of rock strata that have a comparable lithology, facies or other similar properties...

 and is the oldest exposed sediments in Florida

Florida

Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...

, United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

.

Age

Period: Paleogene

Paleogene

The Paleogene is a geologic period and system that began 65.5 ± 0.3 and ended 23.03 ± 0.05 million years ago and comprises the first part of the Cenozoic Era...

Epoch

Epoch (geology)

An epoch is a subdivision of the geologic timescale based on rock layering. In order, the higher subdivisions are periods, eras and eons. We are currently living in the Holocene epoch...

: Middle Eocene

Eocene

The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...

~55.8 to 33.9 mya, calculates to a period of

Faunal stage

Faunal stage

In chronostratigraphy, a stage is a succession of rock strata laid down in a single age on the geologic timescale, which usually represents millions of years of deposition. A given stage of rock and the corresponding age of time will by convention have the same name, and the same boundaries.Rock...

: Clarkforkian

Clarkforkian

The Clarkforkian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology , typically set from 56,800,000 to 55,400,000 years BP lasting . It is usually considered to be within the Paleocene, more specifically the...

 through early Chadronian

Chadronian

The Chadronian age within the North American Land Mammal Ages chronology is the North American faunal stage typically set from 38,000,000 to 33,900,000 years BP, a period of . It is usually considered to fall within the Eocene epoch...

Location

The Avon Park formation is located on the crest of the Ocala Platform

Ocala Platform

The Ocala Platform or Ocala Uplift is a geologic formation, a structural high, and a northwest-trending uplift paralleling the Peninsular Arch along the west coast.-Age:Period: NeogeneEpoch: Early Late Oligocene through Pliocene...

 in Citrus County

Citrus County, Florida

Citrus County is a county located in the U.S. state of Florida. As of 2000, the population was 118,085. The U.S. Census Bureau 2008 estimate for the county was 141,416 . Its county seat is Inverness, Florida...

 with three distinct outcroppings. Levy County

Levy County, Florida

Levy County is a county located in the state of Florida. As of 2000, the population was 34,450. The U.S. Census Bureau 2005 estimate for the county is 37,998. Its county seat is Bronson, Florida. Levy is pronounced lee vee.- History :...

 has one outcropping near the county line with Citrus County.

Composition

The Avon Park Formation consists of cream to light-brown or tan, poorly hardened to very hard, grainstone

Grainstone

Under the Dunham classification, grainstones are grain-supported carbonate sedimentary rocks that contain no micrite. The spaces between grains are filled with sparry cement.-References:...

, packstone and wackestone

Wackestone

Wackestone is a matrix-supported carbonate rock that contains over 10% allochems in a carbonate mud matrix. This is part of the Dunham classification of carbonate rocks. In the other widely used classification due to Folk, an equivalent description would be, for example, an oopelmicrite, where the...

, with rare mudstone

Mudstone

Mudstone is a fine grained sedimentary rock whose original constituents were clays or muds. Grain size is up to 0.0625 mm with individual grains too small to be distinguished without a microscope. With increased pressure over time the platey clay minerals may become aligned, with the...

. Fossils found throughout but not densely. These limestones are interbedded with vuggy dolostone

Dolostone

Dolostone or dolomite rock is a sedimentary carbonate rock that contains a high percentage of the mineral dolomite. In old U.S.G.S. publications it was referred to as magnesian limestone. Most dolostone formed as a magnesium replacement of limestone or lime mud prior to lithification. It is...

s which are soft to very hard and tan to brown, very fine to medium crystalline structure.

The Avon Park Formation, as with many formations, is part of the Floridan Aquifer

Floridan Aquifer

The Floridan Aquifer is a portion of the principal artesian aquifer that extends into Florida and is composed of carbonate rock and located beneath the coastal regions of the Southeastern United States and is one of the world's most productive aquifers. It is under all of Florida as well as ...

 system. Parts of the Avon Park Formation comprise important, subregional confining units within that system.

Fossils

The fossils are in molds and casts and include:

• Mollusks
• Foraminifers
• Echinoids
• Algae
  Algae
  Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
  
  
• Carbonized
  Carbonization
  Carbonization or carbonisation is the term for the conversion of an organic substance into carbon or a carbon-containing residue through pyrolysis or destructive distillation. It is often used in organic chemistry with reference to the generation of coal gas and coal tar from raw coal...
  
  plants