INTRODUCTION. 



Nearly all the remains of the marine Reptilia of the Oxford Clay enumerated and 

 described in this Catalogue, were collected from the numerous clay-pits near Peter- 

 borough worked for the making of bricks, an industry that is extensively carried on in 

 that neighbourhood. A few of the earlier specimens were discovered by Mr. Charles 

 E. Leeds, M.A., but the greater pai't of the collection was made by his brother, Mr. Alfred 

 N. Leeds, F.G.S., of Eyebury, who soon became associated with him. It is more than 

 forty years since the collection was begun by Mr. Charles E. Leeds, and some of his first 

 discoveries were described and figured by Phillips in his ' Geology of Oxford and the 

 Valley of the Thames,' published in 187L He left for New Zealand in 1887, but 

 his brother has continued the work to the present day with the most astonishing 

 results. Both in the number of species represented and in the perfect preser- 

 vation of their remains, the Leeds Collection far surpasses any other single collection of 

 Mesozoic Vertebrates, especially one in which all the specimens are from one horizon 

 and from a restricted area. Not only marine forms, bnt remains of terrestrial 

 reptiles, including several species of Dinosaurs, have been obtained. 



In nearly all cases the specimens have been collected with extreme care, usually by 

 Mr. Leeds himself, the bones of the different parts of the skeleton being numbered 

 and packed in separate parcels. Frequently, portions of the skeleton, such as the 

 skull or limb-girdles, can only be extricated from the clay in fragments, but these 

 have been reunited with the greatest skill and patience by Mr. Leeds. 'J"he 

 consequence of this care is that, in the case of some of the more nearly complete and 

 uncrushed skeletons, it has been possible to mount the bones in their natural relations 



