NOTES ON SOME NEW OR LITTLE-KNOWN EXTINCT 



REPTILES. 



BY S. W. WILLISTON. 

 With Plates XII and XIII. 



Lower Cretaceous Dinosaur. 



Among some material collected from the Comanche Creta- 

 ceous of Clark county, Kansas, several years ago, by Prof. C. 

 N. Gould, there is a nearly complete centrum of a carnivorous 

 dinosaur allied to Creosaurus or Allosaurus. It measures 100 

 mm. in length, 87 in transverse diameter at the extremities, 

 and about 100 in height. The ends are vertically oval and 

 nearly flat; the sides and below are deeply concave in outline. 

 The specimen doubtless represents a new form, but the mate- 

 rial preserved is too incomplete to furnish even generic char- 

 acters. 



This is, I believe, the second specimen of a dinosaur that has 

 been discovered in the Cretaceous of Kansas, the other being 

 the type specimen of Claosaurus agilis Marsh, discovered by 

 Marsh many years ago in the Niobrara Cretaceous of the 

 Smoky Hill valley, in western Kansas. 



New Benton Turtle. (Protostega?) 



The turtles of the genus Protostega have hitherto been known 

 only from the Niobrara Cretaceous of western Kansas, and 

 those of the nearly allied genus Archelon from the Pierre of 

 South Dakota. Several years ago a specimen of a large turtle, 

 belonging either to the genus Protostega or an allied new one, 

 was collected from a lower stratum of the Benton Cretaceous of 

 Kansas by Prof. W. N. Logan. The specimen consists of some 

 fragmentary ribs and a part of a large humerus, apparently 

 larger than that bone in P. gigas. The material does not per- 

 mit a close comparison, however. 



Mosasaurs. 



At different times I have expressed a doubt of the validity of 

 the genus Holosaurus Marsh as distinct from Platecarpus. An 

 examination of the type specimen of the genus has not wholly 



mi) 



