48 



entered the rock, and, on passing round to the opposite side, 'the jaws and 

 muzzle were seen projecting from it, as though laid bare for the ponvenience 

 of the geologist. The spur was small and of soft material, and we speedily 

 removed it in blocks, to the level of the reptile, and took out the remains as 

 they lay across the base from side to side. 



A genus related to the last is Clidastes. They did not reach such a size 

 as some of the Liodons, and were of elegant and flexible build. To prevent 

 their contortions from dislocating the vertebral column, these had an addi- 

 tional pair of articulations at each end, while their muscular strength is 

 attested by the elegant striae and other sculptures which appear on all their 

 bones. Ten species of this genus occur in the Kausas strata, the largest 

 {Clidastes cineriarum, Cope) reaching forty feet in length. A smaller species, 

 of elegant proportions, has been called C. tortor, Cope. Its slenderness of body 

 was remarkable, and the large head was long and lance-shaped. Its lithe 

 movements brought many a fish to its knife-shaped teeth, which are more 

 efficient and numerous than in any of its relatives. It was found coiled up 

 beneath a ledge of rock, with its skull lying undisturbed in the center. A 

 species distinguished for its small size and elegance, is C. pumilus, Marsh. 

 This little fellow was only twelve feet in length, and was probably unable to 

 avoid occasionally furnishing a meal for some of the rapacious fishes which 

 abounded in the same ocean. 



The flying saurians are pretty well known from the descriptions of 

 European authors. Our Mesozoic periods had been thought to have lacked 

 these singular forms until Professor Marsh and the writer discovered remains 

 of species in the Kansas chalk. Though these are not numerous, their size was 

 formidable. One of them (Ptcrodactylus occideutalis, Marsh) spread eighteen 

 feel between the tips of its wings, while the P. umbrosus, Cope, covered 

 nearly twenty-five feet with his expanse. These strange creatures flapped their 

 leathery wings over the waves, and, often plunging, seized many an unsuspect- 

 ing fish ; or, soaring at a safe distance, viewed the sports and combats of the 

 more powerful saurians of the sea. At night-fall, we may imagine them 

 trooping to the shore, and suspending themselves to the cliffs by the claw- 

 bearing lingers of their wing-limbs. 



Tortoises were the boatmen of the Cretaceous waters of the eastern 

 toast, but none had been known from the deposits of Kansas until very 

 recently. Tin- largesl species on record (Protostega gigas, Cope) is strange 



