CONTENTS, 



i-AGE 



Preface ••......„ 



Memoir on the Extinct Reptiles of the Cretaceous Formations of the United States . . . 1 



Introduction ............. . . 1 



Sauria ................. 5 



Thoracosaurus heocesariensis .............. 5 



Bottosaurus Harlani .............. 12 



Undetermined Species of Crocodiles I4 



Hyposaurus Rogersii .18 



Discosaurus vetustus .............. 22 



Cimoliasaurus magnus . 2.5 



Piratosaurus plicatus .............. 29 



Mosasaurus ... ............. 30 



Macrosaurus Isevis . 74 



Polygonodon vetus 76 



Hadrosaurus Poulkii .............. '76 



Undetermined Reptiles allied to Hadrosaurus .......... 97 



Astrodon Johnstoni . . . . . .102 



Tomodon horrificus . 102 



Pliogonodon priscus 103 



Chelonia ................ 104 



Chelone sopita 104 



Chelone ornata 105 



Emys firmus . . ■ 106 



Emys beatus 107 



Emys pravus 108 



Platemys sulcatus . 109 



Bothremys Cookii 110 



Trionyx priscus . 113 



A Synopsis, in which an attempt is made to define more closely th^ Genera and Species whose 



remains are described in the preceding pages 115 



Index 121 



References to the Plates 123 



( V ) 



