GEOLOGICAL SOCIETY OF PENNSYLVANIA. 



351 



ing in a line much over 100 feet in length. This state- 

 ment agrees with that made by Judge Bree; 150 feet in 

 length being attributed by the observers to the Arkansa 

 skeleton. The comparative smallness of the bones of 

 the extremities or fins, constrains us to look to the tail 

 of the animal for the principal organ of locomotion of this 

 huge mass. 



Place in the geological series — most recent of the 

 cretaceous groupe. Mr Conrad considers this horizontal 

 limestone rock of Alabama as more recent than the true 

 chalk of Europe, and even as occupying a place anterior 

 to the Maestricht beds. For the accurate and beautiful 

 drawings illustrative of these fossils, we are indebted to 

 the skill and kindness of our friend Richard C. Taylor, 

 Esq. who liberally offered his services con amore'' 

 when his time was most precious to him. Such accurate 

 illustrations obviate in a great measure the necessity of 

 minuteness in written details. ^ 



Superior maxilla. PI. 22, Jig. 1. 



This fragment constitutes the most important portion 

 of the new fossil animal hitherto brought to view; it con- 

 sists of a considerable portion of the upper jaw of the 

 right side, containing four teeth more or less fractured, 

 together with the sockets of two others : these, like most 

 of the bones, are of a light brown colour slightly tinged 

 with red; they are so extremely brittle, and so inti- 

 mately consolidated and incorporated with the rock, as 

 to render their separation almost impracticable. That 

 portion of the palate bone remaining is nearly on a level 

 with the alveoles; the side of the jaw presents a doubly 

 concave surface, that is, concave from above downwards, 

 and from before backwards ; the superior border is con- 

 vex posteriorly, and slightly concave before : this bone 

 is unusually thin, and at the alveoles barely sufficient to 

 accommodate the roots of the teeth. PI. 24, fig. 2, dis- 



