CRETACEOUS STRATA OF OTHER COUNTRIES. 



313 



the Monitor and Iguana, about twenty-five feet long ; it 

 was furnished with a tail of such construction, as must have 

 rendered it a powerful oar, enabling the animal to stem the 

 waves of the ocean, of which Cuvier supposes it to have 

 been an inhabitant. 



In the English chalk a few remains of this reptile have 

 been met with. I collected three vertebras from the 

 upper chalk near Lewes, many years since;* and have 

 recently obtained a caudal vertebra from Kemp-tow r n, near 

 Brighton ; the latter is partially invested with flint, which 

 has consolidated around it without obscuring its essential 

 characters. 



Some teeth, from North America, collected by Dr. 

 Morton of Philadelphia, appear to be of the same species 

 as those from Maestricht, and afford additional proof of the 

 extension of the waters of the chalk ocean over the area 

 now occupied by the Atlantic, and part of the dry land of 

 North America.j" 



13. Cretaceous strata of other countries. — In the 

 north of France the same characters predominate ; but in 

 the south, the group is more or less calcareous throughout ; 

 and the lower division, w r hich is the representative of our 

 greensands and clays, consists of calcareous beds, with 

 white limestone and tufaceous marlstone. 



In Central and Eastern Germany the entire system is 

 more siliceous, calcareous matter being very sparingly dis- 

 tributed. In Saxony it consists of siliceous sandstone — 

 conglomerates, chert, and ferruginous sand and sandstone — 

 calcareous grit containing the w^ell known gait shell, Inoce- 

 ranus concentricus — and calcareous rock with haroites, 

 scaphites, terebratulae, and plagiostoma; the uppermost 

 strata yielding a siliceous building stone. 



* Fossils of the South-East of England, p. 146. 

 f See Dr. Morton's Synopsis of the Cretaceous Strata of the United 

 States. 



