formation

Formation d'âge Kimmeridgien (jaune orangé) et Tithonien (Barre tithonique, en gris sur la photo). On peut remarquer que les strates ont été plissées. L'âge des mouvements tectoniques ayant déformé la structure est donc plus jeune que le Tithonien.

The GSSP for the Hirnantian stage in the ICS geological timescale (uppermost Ordovician stage), located in the Wangjiawan profile (an outcrop of black shale, brownishly weathered siliceous shale and chert layers of the Wufeng Formation) along the G241 road, about 40 km north of Yichang, Hubei, China. An exact golden spike is missing in the profile (2025) but a memorial plague marks the place. The GSSP occurs at the first appearance of fossils of the graptolite species Normalograptus extraordinarius. It was ratified in 2006.

Danian microflora - Lefipán Formation, Cañadón Asfalto Basin, Patagonia, Argentina

Fossiliferous limestone of the Roca Formation (Danian) in Barda Norte, the type locality of the Roca Formation, General Roca, Río Negro, Patagonia, Argentina.

Quarry called “Ratssteinbruch” at Plauenscher Grund (gorge-like valley of the river Weißeritz nearby/in the city of Dresden, Saxony, Germany), Upper Carboniferous Monzonite (historically identified as Syenite) of the Meißen Massif (Paleozoic basement) unconformably overlain by Upper Cenomanian beds of the Dölzschen Formation, yellowish basal conglomerate and overlying bluish silty clay-marlstone (“plenus-Pläner”) of the Saxo-Bohemian Cretaceous Basin (Mesozoic platform).[1]

Sandstones of the lower Kirtland Formation (Late Campanian), outcropping near Coal Creek. New Mexico. Photo by Nick Longrich

A fossil tree from the Coal Creek region, Fruitland Formation, latest Cretaceous (Late Campanian), San Juan Basin, New Mexico

Holotype skull of the centrosaurine ceratopsian dinosaur Diabloceratops eatoni from the Late Cretaceous (Campanian) of the Wahweap Formation, Grand Staircase-Escalante National Monument, Utah. Photograph by Nick Longrich, 2023.

Outcrops of the Late Cretaceous (Campanian) aged Aguja Formation, Big Bend National Park, Texas, USA

Osgodby Formation (Middle Jurassic) exposed on the shore of Cayton Bay, North Yorkshire.

Matmor Formation (Jurassic, Callovian) exposed in Makhtesh Gadol, Israel. (Electricity pylon for scale).

An atypical (without intertidal and supratidal environment) carbonate platform settles down along the margin. Shallow water oolithes and oncoids are deposited in a narrow zone between a basin with Cancellophycus to the north and a marine/swampy plain with abundants mollusc fauna. However the Mytilus formation, rich in bathonian and callovian foraminifera (Septfontaine, 1984 etc.), develop thick limestone beds tenth of meter above, wrongly attributed to the upper Jurassic. See discussion in Septfontaine (1984).

Life restoration of Cearadactylus atrox. Based on figure 2 of "On the systematic relationships of Cearadactylus atrox, an enigmatic Early Cretaceous pterosaur from the Santana Formation of Brazil" by D. M. Unwin Mitteilungen Museum für Naturkunde Berlin, Geowissenschaftlichen Reihe 5: 239-263

A photograph of partial specimen American Museum of Natural History (AMNH) 22555, skull without mandible, of Anhanguera sp. (formerly often assigned to Anhanguera santanae),[1] from the Early Cretaceous Romualdo Formation (former Romualdo Member of the Santana Formation) of NE Brazil in right lateral view.

A photograph of partial specimen American Museum of Natural History (AMNH) 22555, anterior dorsal vertebrae, dorsal ribs and partial shoulder girdle (at least right scapula) of Anhanguera sp. (formerly often assigned to Anhanguera santanae),[1] from the Early Cretaceous Romualdo Formation (former Romualdo Member of the Santana Formation) of NE Brazil in dorsal view.

A photograph of partial specimen American Museum of Natural History (AMNH) 22555, posterior dorsal vertebrae, and the sacrum and pelvis (both iliae, and right ischium and pubis) of Anhanguera sp. (formerly often assigned to Anhanguera santanae),[1] from the Early Cretaceous Romualdo Formation (former Romualdo Member of the Santana Formation) of NE Brazil in dorsal view.