formation

Map of Grand Staircase-Escalante National Monument (GSENM), southern Utah (A), and generalized stratigraphic section of the upper Campanian Kaiprowits Formation (B). The approximate stratigraphic position of Akainacephalus johnsoni is located near the base of the middle unit within the Kaiparowits Formation. The map highlights the GSENM boundary (dashed line), showing the geological distribution and outcrops of the Cretaceous Kaiparowits, Wahweap, and Straight Cliffs formations. The red star indicates the Horse Mountain area, from which Akainacephalus johnsoni was recorded. Map and stratigraphic column modified from Roberts (2005). Radioisotopic dates used from Roberts, Deino & Chan (2005) and Roberts et al. (2013), respectively.

Psittacosaurus skeletal mount (Early Cretaceous, Jiufotang Formation) and unidentified Late Cretaceous dinosaur egg from Xixia, Hennan, on display in the Li Siguang Memorial Museum in Huangzhou.

Shestakovsky Yar (paleontological site Shestakovo-1, Ilek Formation).

Paleontological locality Shestakovo 3 (Ilek Formation, Lower Cretaceous), July 2022.

(A) Present day map of Australia with the town of Lightning Ridge indicated by the star. (B) Regional map of the Lightning Ridge region showing localities (where known) for specimens described in this text. Sealed (solid black lines) and unsealed roads (dashed lines) are indicated. The ephemeral Coocoran Lake is marked with a dotted blue line. (C) Correlative stratigraphy of the major Cretaceous depositional basins and geological units discussed in this study. The ornithopod icon and arrow indicate the approximate level of the Griman Creek Formation from which the current material pertains. Informal units are in quotation marks. Maps in (A) and (B) redrawn and modified from Bell et al. (2016) and Opal Fields—Lightning Ridge Region map produced by the NSW Department of Mineral Resources, respectively. Stratigraphy based on Toslini, McLoughlin & Drinnan (1999) and Cook, Bryan & Draper (2013). Ornithopod silhouette created by Caleb M. Brown and used under the Creative Commons Attribution-ShareAlike 3.0 Unported license.

View north across Frenchman River of Upper Cretaceous and Paleocene age strata of the Bearpaw, Whitemud, Battle, Frenchman, and Ravenscrag Formations in the Cypress Hills of southern Saskatchewan. Foreground strata on other side of (tree lined) creek represent a slumped section. Note the bright white zone is the Whitemud Formation. View includes type area of Frenchman and Ravenscrag Formations.

View northeast across Frenchman River of Upper Cretaceous and Paleocene age strata of the Bearpaw, Whitemud, Battle, Frenchman, and Ravenscrag Formations in the Cypress Hills of southern Saskatchewan. Foreground strata on other side of (tree lined) creek represent a slumped section. Note the bright white zone is the Whitemud Formation. View includes type area of Frenchman and Ravenscrag Formations.

Dryolestidan mammal Crusafontia amoae sp. nov., MPZ CC2−1 M4 or M5, holotype, from the site of Cuesta Corrales 2, Colladico Blanco level, El Castellar Formation, Galve, Teruel, Spain in, occlusal (A), mesial (B), labial (C), distal (D), and lingual (E) views. The schematic drawing of C. amoae, in the box in the lower left−hand corner shows the main anatomical elements of the occlusal surface of a dryolestidan.

The type specimen of the ichnogenus Cheliceratichnus, from the Early Jurassic East Berlin Formation of Holyoke, Massachusetts.

Bifurculapes laqueatus trackway (positive hyporelief, i.e. casts on the bottom surface of the bed) from the Early Jurassic East Berlin Formation (Hartford Basin) of Holyoke, Massachusetts (not the same specimen as this one). See coin (1 U.S. cent, 19.05 mm in diameter) for scale.

Bifurculapes laqueatus trackway (positive hyporelief, i.e. casts on the bottom surface of the bed) from the Early Jurassic East Berlin Formation (Hartford Basin) of Holyoke, Massachusetts (not the same specimen as this one). See coin (1 U.S. cent, 19.05 mm in diameter) for scale.

A trackway of the trace fossil Bifurculapes laqueatus (positive hyporelief, i.e. casts on the bottom surface of the bed) from the Early Jurassic East Berlin Formation (Hartford Basin) of Holyoke, Massachusetts (not the same specimen as this one). Scale is in cm.

Geological context of the Lower Cretaceous deposits of southeast England, focussing on the Purbeck Group and Wealden Supergroup. (A) Schematic geology of the Lower Cretaceous deposits of the Weald Sub-basin (southeast England), highlighting published spinosaurid finds (Charig & Milner, 1997; Salisbury & Naish, 2011; Turmine-Juhel et al., 2019). Based on Austen & Batten (2018: Fig. 2). Note that various additional spinosaurid teeth are known from the region but remain undescribed in detail (Fowler, 2007). (B) Simplified stratigraphic column of the Weald Group in southeast England, based on Batten & Austen (2011: Fig. 3.2). Note that the Grinstead Clay Formation, which subdivides the Tunbridge Wells Sands Formation in Batten & Austen (2011) and from which the “Suchosaurus cultridens” type specimen was discovered (Salisbury & Naish, 2011), is downgraded to a member of the latter formation in other works (Hopson, Wilkinson & Woods, 2008) and has not been included in this column. Spinosaurid silhouette courtesy of Dan Folkes (CC-BY 4.0).

Type section of the Cedar Mountain Formation, western side of Cedar Mountain, Emery County, Utah.

Morrison Formation (lower half), Jurassic-Cretacous boundary (K1 Unconformity) at red and orange paleosol, Cedar Mountain Formation (drab gray), and capping Naturita Formation. West of Dinosaur National Monument.

Brushy Basin Member of the Morrison Formation (multi-colored) unconformably overlain by the Yellow Cat Member of the Cedar Mountain Formation (drab color), Jessie's Twist, Emery County, Utah