72 EXTINCT MONSTERS. 



during the Jurassic period probably in an old estuary. They 

 consist of shale and sandstone. 



Besides the numerous Dinosaurs, Professor Marsh's colleagues 

 have found abundant remains of crocodiles, tortoises, and fishes, 

 with one Pterodactyl, a flying reptile (see chap, viii.), and several 

 small marsupials. The wonderful collection of American Jurassic 

 Dinosaurs in the Museum of Yale College includes the remains 

 of several hundred individuals, many of them in excellent pre- 



2 



FIG. II. Head of Diplodocus. 

 I. Side view. 2. Front view. 



servation, and has afforded to Professor Marsh the material for 

 his classification already alluded to. 



ENGLISH DINOSAURS OF THE LIZARD-FOOTED GROUP. 



Unfortunately, there are at present no complete skeletons known 

 of English Dinosaurs related to the American forms above de- 

 scribed. But, since the English fossils were first in evidence by 

 many years, and Marsh's discoveries have confirmed in a remark- 

 able way conclusions drawn by Owen, Huxley, Hulke, and Seeley, 

 and others from materials that were rather fragmentary, it may be 

 worth while to give some account of these remains and the inter- 

 pretations they have received. 



Dr. Buckland, in his Bridgewater Treatise, 1836, referred to 



