the Early Cretaceous Cambridge Greensand produced thousands of pterosaur fossils, that however, were of poor quality, consisting mostly of strongly eroded fragments. Nevertheless, based on these, numerous genera and species would be named. Many were described by Harry Govier Seeley, at the time the main English expert on the subject, who also wrote the first pterosaur book, Ornithosauria, and in 1901 the first popular book, Dragons of the Air. Seeley thought that pterosaurs were warm-blooded and dynamic creatures, closely related to birds. Earlier, the evolutionist St. George Jackson Mivart had suggested pterosaurs were the direct ancestors of birds. Owen opposed the views of both men, seeing pterosaurs as cold-blooded "true" reptiles. In the US, Othniel Charles Marsh in 1870 discovered Pteranodon in the Niobrara Chalk, then the largest known pterosaur, the first toothless one and the first from America. These layers too rendered thousands of fossils, also including relatively complete skeletons that were three-dimensionally preserved instead of being strongly compressed as with the Solnhofen specimens. This led to a much better understanding of many anatomical details, such as the hollow nature of the bones. Meanwhile, finds from the Solnhofen had continued, accounting for the majority of complete high quality specimens discovered. They allowed to identify most new basal taxa, such as Rhamphorhynchus, Scaphognathus and Dorygnathus. This material gave birth to a German school of pterosaur research, which saw flying reptiles as the warm-blooded, furry and active Mesozoic counterparts of modern bats and birds. In 1882, Marsh and Karl Alfred Zittel published studies about the wing membranes of specimens of Rhamphorhynchus. German studies continued well into the 1930s, describing new species such as Anurognathus. In 1927, Ferdinand Broili discovered hair follicles in pterosaur skin, and paleoneurologist Tilly Edinger determined that the brains of pterosaurs more resembled those of birds than modern cold-blooded reptiles. In contrast, English and American paleontologists by the middle of the twentieth century largely lost interest in pterosaurs. They saw them as failed evolutionary experiments, cold-blooded and scaly, that hardly could fly, the larger species only able to glide, being forced to climb trees or throw themselves from cliffs to achieve a take-off. In 1914, for the first time pterosaur aerodynamics were quantitatively analysed, by Ernest Hanbury Hankin and David Meredith Seares Watson, but they interpreted Pteranodon as a pure glider. Little research was done on the group during the 1940s and 1950s. Pterosaur renaissance The situation for