formation

The productive layer of the Estonian oil shale deposit as seen in the Põhja-Kiviõli II opencast mine. The productive layer is made up of oil shale layers A through F1 together with the limestone layers in between. However, in some cases, layers F2, G and H (visible in the image, but not labeled) are also mined. The oil shale beds are marked on the image with capital letters, limestone layers are labeled with a combination of two capital letters, indicating at their location within the productive layer. Dashed lines indicate layer boundaries, which are harder to distinguish and are thus approximations. Stratigraphy: the productive layer of the Estonian oil shale deposit is part of the Kiviõli Member of the Viivikonna Formation. The formation belongs to Upper-Ordovician Kukruse Regional Stage (global Sandbian Stage). (Source reference: Heikki Bauert and Olle Hints "XI Baltic Stratigraphical Conference. Abstracts and Field Guide", Stop 4: Põhja-Kiviõli II open-pit mine, page 85, figure 4.4).

Shetwemys, Plastral remains of the podocnemidid turtle S. fajumensis (Erymnochelyini). (a–b) NHMUK R3435, anterior plastral lobe, in ventral (a) and dorsal (b) views. (c–d) NHMUK R8441, plaster cast of the specimen CGM C8509, anterior plastral lobe, in ventral (c) and dorsal (d) views. (e–f) AMNH 5093, articulated epiplastra and entoplastron, in ventral (e) and dorsal (f) views. (g–h) SMNS 11233/6, anterior plastral lobe, in ventral (g) and dorsal (h) views. (i–j) NHMUK R3103, partial anterior plastral lobe, in ventral (i) and dorsal (j) views. (k–l) SMNS 11233/5, right hypoplastron, in ventral (k) and dorsal (l) views. (m–n) SMNS 11233/3, articulated left hypoplastron and xiphiplastron, in dorsal (m) and ventral (n) views, and detail of the outer ornamental pattern (o). Gebel Quatrani Formation, Fayum depression, Egypt, Lower Oligocene (Rupelian)

Shetwemys, Shell remains of the podocnemidid turtle S. fajumensis (Erymnochelyini). (a–c) SMNS 11233/2, partial carapace, in dorsal (a), ventral (b), and left lateral (c) views. (d) Ventral view of the anterior lobe the holotype of the species, currently lost, based on the fig. 2C in plate 8 of Andrews (1903). (e–g) SMNS 12647, plastron, in ventral (e), dorsal (f), and left lateral (g) views. (g’) corresponds to an enlarged photograph of the posterior plastral lobe, in left lateral view, in which the thickness in the regions close to the hypo-xiphiplastral suture (in blue), between the pelvic scars (in green), and at the level of the anal notch (in red), have been represented by arrows (h–i), SMNS 12646, plastron, in ventral (h) and dorsal (i) views. Gebel Quatrani Formation, Fayum depression, Egypt, Lower Oligocene (Rupelian)

Shetwemys, Shell remains of the podocnemidid turtle S. fajumensis (Erymnochelyini). (a–f) AMNH 5087, carapace and partial plastron, in dorsal (a), ventral (b), anterior (c), posterior (d), left lateral (e), and right lateral (f) views. (g–h) SMNS 11233/1, partial carapace, in dorsal (g) and ventral (h) views. Gebel Quatrani Formation, Fayum depression, Egypt, Lower Oligocene (Rupelian)

Close up of the Eulithomyrmex rugosus holotype head. Museum of Comparative Zoology specimen UCM17019. Priabonian; Florissant Formation, Colorado, USA

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).