Jurassic dinosaur tracks and trackways of the

SUMMARY: Dinosaur tracks are abundant in the Middle Jurassic rocks of Yorkshire and indeed characterize the non-marine sequences developed within the Cleveland Basin. These tracks and associated trackways provide valuable evidence of the possible diversity of the dinosaur communities, their potential makers and behaviour and useful insights into the habitats and palaeo-environment during the time of deposition. The uneven historical development of research into Yorkshire dinosaur tracks is reviewed and the Middle Jurassic lithostratigraphy, biostratigraphy and chronostrat igraphy of the region is outlined. Next, the probable palaeoenvironment of the Middle Jurassic Cleveland Basin, generally regarded as a coastal plain and fluvial complex, is briefly summarized. The terminology used to describe the dominant preservational types of dinosaur tracks, such as surface, trans-mitted and underprints, is clearly defined, with examples from the Yorkshire sequences. The Yorkshire tracks show considerable morphological diversity and at present 29 different morphotypes have been recognized, which possibly represent at least 15 ich-notaxa. These morphotypes include both quadrupedal and bipedal forms, as well as a distinctive suite of raking prints resulting from swimming activity. The distribution and abundance of the known dinosaur tracks within the Middle Jurassic rocks of York-shire is described. For the first t ime, a range chart of dinosaur tracks is presented that illustrates the persistence of some morpho-types throughout the Ravenscar G r o u p (Middle Jurassic) of the Cleveland Basin. Track distribution and diversity data allow reconstruction of the Yorkshire dinosaur communit ies that were made up of be tween 7-10 common types, belonging to sauropods, stegosaurids, orni thopods and theropods. The area is a 'megatracksi te ' of global importance