THE ANNALS 



AND 



MAGAZINE OF NATURAL HISTOEY. 



[FIFTH SERIES.] 

 No. 9. SEPTEMBER 1878. 



XXIV. — On the Occurrence in North America of rare Extinct 

 Vertebrates found fragmentarily in England. By Prof. 

 E, Owen, C.B., RR.S., &c. 



[Plates X, & XI.] 



Part I. Restoration of Csondrosteosau:rus. 



Of such species, one of the most, if not the most, extraordi- 

 nary which has come under my observation is the extinct 

 reptile on certain vertebrae of which I founded, in 1876, the 

 genus Chondrosteosaurus and the species Ch. gigas^. 



The centrum of an " anterior trunk- vertebra," the position 

 of which, by characters continued, in Crocodilus^ from the 

 posterior co-vicals to the anterior dorsals, I would not more 

 precisely define, presented a length of 1 foot 3 inches (375 

 millims.). Another and more posterior vertebral centrum, and 

 a third more mutilated one, of which I made a section showing 

 its imperfectly ossified structure, were, and still are, all the 

 evidences of Chondrosteosaurus which have reached me from 

 British Wealden strata : the locality was the submerged bed 

 on the south coast of the Isle of Wight. 



I am of opinion, however, that our knowledge of this huge 

 and singular Saurian has been extended by discoveries, in 

 1877, of fossil remains in the Mesozoic formations of Fremont 

 County, Colorado, U. S., due to the persevering researches of 

 the Superintendent of Public Schools in that county, Mr. O. 

 W. Lucas. 



* " Monograpli on the Fossil Reptilia of the Wealden Formations," in 

 the Palseontographical Society's volume issued in 1876, p. 5, pis. ii.-v. 



Ann. dc Mag. N. Hist. Ser. 5. Vol. ii. 14 



