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Neotheropoda represents the main evolutionary radiation of predatory dinosaurs and its oldest records come from Upper Triassic rocks (c. 219 Mya). The Early Jurassic record of Neotheropoda is taxonomically richer and geographically more widespread than that of the Late Triassic. The Lower Jurassic (upper Hettangian–lower Sinemurian) rocks of central England have yielded three neotheropod specimens that have been assigned to two species within the genus Sarcosaurus, S. woodi (type species) and S. andrewsi. These species have received little attention in discussions of the early evolution of Neotheropoda and recently have been considered as nomina dubia. Here, we provide a detailed redescription of one of these specimens (WARMS G667–690) and reassess the taxonomy and phylogenetic relationships of the genus Sarcosaurus. We propose that the three neotheropod specimens from the Early Jurassic of central England represent a single valid species, S. woodi. The second species of the genus, ‘S. andrewsi’, is a subjective junior synonym of the former. A quantitative phylogenetic analysis of early theropods recovered S. woodi as one of the closest sister-taxa to Averostra and provides new information on the sequence of character state transformations in the lead up to the phylogenetic split between Ceratosauria and Tetanurae.

Nodular soil carbonates (calcretes) are present in overbank facies of Lower Cretaceous, non-marine Wealden Beds (Wessex Formation) of southern England. Field evidence suggests that these calcretes formed mostly under semi-arid Mediterranean-type climatic conditions. Typical calcrete fabrics, identified petrographically, include floating detrital grains, corroded grain margins and circumgranular cracks defining peds. Localized alteration of primary micrites is mainly associated with large cracks where early non-ferroan diagenetic cementation and neomorphism was focused. Diagenetic ferroan calcites occur as void fills and yield relatively light carbon-isotope and oxygen-isotope compositions ( 13 C= 15.0‰; 18 O= -6.3‰) compared to well-preserved micrite ( 13 C= -10.2‰; 18 O= -4.0‰). Precise definition of 13 C values for well-preserved micrites allow estimation of partial pressure of atmospheric CO 2 (pCO 2 ) for the early Barremian of 560 ppmV using a published diffusion-reaction model. The data suggest that atmospheric CO 2 was low during the mid-Early Cretaceous before rising to a previously defined mid-Cretaceous high. Data from calcretes in the Weald Clay highlight the need for selection of appropriate material and careful evaluation before pCO 2 calculations are attempted. The Weald Clay samples come from marshy palaeoenvironments where ingress of atmospheric CO 2 into the soil-zone was either reduced or prevented.

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The Wealden strata of southern England provide a range of evidence for Early Cretaceous non‐marine environments and their inhabitants, and a climate of warm to hot, ‘Mediterranean’ aspect. Because of its exposure, and its range of facies, distinguishing a variety of sedimentary environments, the Wealden has long fascinated geologists intent on providing an environmental model. This article is one of two intended to give an overview of Wealden environments, providing the geological framework of these strata. In this article, the type‐succession in the Weald Sub‐basin of south‐east England is summarized and briefly interpreted.