Tithonian
In the geological timescale, the Tithonian is the latest age of the Late Jurassic Epoch and the uppermost stage of the Upper Jurassic Series. It spans the time between 152.1 ± 4 Ma and 145.0 ± 4 Ma (million years ago). It is preceded by the Kimmeridgian and followed by the Berriasian (part of the Cretaceous). Stratigraphic definitions. The Tithonian was introduced in scientific literature by German stratigrapher Albert Oppel in 1865. The name Tithonian is unusual in geological stage names because it is derived from Greek mythology. Tithonus was the son of Laomedon of Troy and fell in  love with Eos, the Greek goddess of dawn. His name was chosen by Albert Oppel for this stratigraphical stage because the Tithonian finds itself hand in hand with the dawn of the Cretaceous. The base of the Tithonian stage is at the base of the ammonite biozone of "Hybonoticeras hybonotum". A global reference profile (a GSSP or golden spike) for the base of the Tithonian had in 2009 not yet been established. The top of the Tithonian stage (the base of the Berriasian Stage and the Cretaceous System) is marked by the first appearance of small globular calpionellids of the  species "Calpionella alpina", at the base of the Alpina Subzone . Subdivision. The Tithonian is often subdivided into Lower/Early, Middle and Upper/Late substages or subages. The Late Tithonian is coeval with the Portlandian Age of British stratigraphy. The Tithonian stage contains seven ammonite biozones in the Tethys domain, from top to base: Sedimentary environments. Sedimentary rocks that formed in the Tethys Ocean during the Tithonian include limestones, which preserve fossilized remains of, for example, cephalopods. The Solnhofen limestone of southern Germany, which is known for its fossils (especially "Archaeopteryx"), is of Tithonian age.