Editing Calvert Cliffs State Park (section)

==Natural history==
===Geology===
The park contains the [[type locality (geology)|type locality]] site of the Early to Middle [[Miocene]] [[Calvert Formation]].<ref name=mgs2/><ref name=vogt>{{cite book|author-last1=Vogt|author-first1=Peter|author-last2=Eshelman|author-first2=Ralph E.|author-last3=Godfrey|author-first3=Stephen J.|editor-last=Godfrey |editor-first=Stephen J.  |title=The Geology and Vertebrate Paleontology of Calvert Cliffs, Maryland [Smithsonian Contributions to Paleobiology; no. 100])|chapter=Calvert Cliffs: Eroding Mural Escarpment, Fossil Dispensary, and Paleoenvironmental Archive in Space and Time |date=2018 |publisher=Smithsonian Institution Scholarly Press |location=Washington, DC |url=https://purl.fdlp.gov/GPO/gpo117196 |access-date=10 March 2019}}</ref> These rocks are the [[sediment]] from a coastal ocean that covered the area during that time. The age of the formation is (19-)18–15(-14) [[million years ago]] ([[Megaannum#SI prefix multipliers|Ma]]), i.e. it extends essentially over the [[Hemingfordian]] [[NALMA|stage]]. This formation occurs in Maryland and neighboring [[Virginia]].  The cliffs are between {{convert|20|-|40|m|order=flip}} high and extend for {{convert|40|km|order=flip}} along the coast.<ref name=vogt />

In addition, rocks of the younger [[Choptank Formation|Choptank]] and the [[St. Marys Formation]]s are exposed here. This makes Calvert Cliffs State Park extremely interesting for its [[paleoclimatology]] and [[paleontology]], because the accessible [[Stratum|strata]] provide a good record of the [[Middle Miocene Climate Transition]] and document a minor [[mass extinction event]] — the "[[Middle Miocene disruption]]." [[Fossil]] collecting and "[[rockhound]]ing" are permitted on the beach; the cliffs are closed due to the dangers of erosion.<ref name=mdnr/>

===Paleontology===
[[File:Calvert Zone 10 Calvert Co MD 2.jpg|thumb|left|Fossils from the Calvert Formation, Zone 10, Calvert Co., MD (Miocene)]]
The [[Calvert Formation]] is notable for its plentiful fossil [[shark]] teeth. Especially popular among "rockhounds" are those from giants such as ''[[Carcharocles]]'' and the famous [[megalodon]]<ref name=guy/> (which is often included in ''Carcharocles'').

The ancestral [[baleen whale]] ''[[Eobalaenoptera harrisoni]]'' and the [[merganser]] ''Mergus miscellus'' were described from the Virginian part of the formation. From the uppermost layer, deposited 15–14 Ma, they represent the oldest known member of their [[family (biology)|family]] and [[genus]], respectively. Some remains of a prehistoric [[loon]] (''Gavia'') from the lowermost parts of the Calvert Formation, dating back nearly 18 Ma, are the oldest records of that genus from North America, and among the oldest worldwide. Fossils of the [[Swordfish|sword fish]]-like [[Eurhinodelphis|Eurhinodelphis longirostris]]<ref>{{Cite web|url=https://www.si.edu/object/eurhinodelphis-longirostris:nmnhpaleobiology_3431163 |title=Eurhinodelphis Longirostris |publisher=National Museum of Natural History |access-date=18 April 2020}}</ref> have been found in zone 14 of the formation.

Other notable baleen whales from this area include a ''[[Cephalotropis|Cephalotropis coronatus]]''. One was discovered by hobbyist paleontologist Jeffery DiMeglio in 2004 after cliff erosion caused by [[Hurricane Isabel]] exposed the skull and scapula.<ref name=hurricane/> Mandibles, neck vertebrae, and scapulae were also found during the dig. The skull and vertebrae are on display at the [[Calvert Marine Museum]].<ref name=museum/> Other items found in the field jackets of the whale were fish bones, hundreds of mollusks, a ''[[Hexanchus|Hexanchus gigas]]'' tooth, and two ''[[Carcharodon|Carcharodon hastalis]]'' teeth.