158 



Mosasaurus, in no respect differing from those collected at Maes- 

 triclit. 



Mr. Rogers recovers the Chalk formation on the banks of the 

 Missouri, and about the mouth of the Omawhaw ; its transverse 

 limit is not known. No flints appear in the beds, but flint nodules, 

 like the English, occur plentifully lower down the river, even to the 

 Mississippi. 



The Ferruginous Sand of America reposes in the northern states 

 of the Union as in Sweden and along the Carpathian mountains, 

 upon primary rocks ; in the southern, upon limestone, perhaps our 

 mountain limestone ; it forms an irregular crescent, extending 

 nearly three thousand miles, through Jersey, Delaware, Maryland, 

 Virginia, the two Carolinas, Georgia, Alabama, Mississippi, Te- 

 nessee, Louisiana, Arkansa and Missouri. 



Dr. Morton and Mr. Rogers refer this formation to the Green-Sand 

 of England with more confidence perhaps than their observations 

 warrant. Sands red and green occur in Europe both above the 

 chalk and below it. Zoological evidence rather militates against their 

 conclusion. With one or two exceptions all the species are peculiar 

 to the western continent. Peden quinquecostatus , the only shell 

 which is quoted as being common to the sands of the United States 

 and this country, occurs also at Maestricht, and Baculites are cha- 

 racteristic of the upper part of the chalk. From the occurrence of 

 great quantities of lignite in this formation, from the remains dis- 

 covered in it of the Scolopas, a bird which inhabits the sea-shore, 

 and from the locality of the beds in reference to the ancient coast 

 line, Mr. Rogers infers that the deposit took place in shallow water, 

 along a coast, which like the present, presented a very extensive 

 range of soundings ; to this circumstance he attributes the differ- 

 ence of the American and European species of sea shells at the 

 same period. 



With greater probability, as far as the evidence of fossils is con- 

 cerned, Mr. Rogers attributes to the Green-Sand Formation of En- 

 gland a deposit traced from below the Big Bend to the Rocky Moun- 

 tains both on the Missouri and the Yellow River, characterized by 

 Karaites, Gryphcjea Columba, and Belemnites compressus. Above the 

 Big Bend horizontal beds of lignite, sandstone, shale and clay, occur 

 continuously for several days journey. The author considers this 

 formation to be of more recent birth ; it contains, near the Cherry 

 River, beds of lignite from three to nine feet in thickness. 



The New Red Sandstone, with its usual accompaniments of sand 

 and gypsum, appears to be in North America developed very ex- 

 tensively. According to Mr. Rogers, it comprehends all the coun- 

 try from the falls of the Platte to the great salt lake, or rather sea, 

 on the western side of the Rocky Mountains, and from the Missouri 

 to the Arkansas and Rio Colorado. The same formation is sup- 

 posed to extend into Mexico, and to be the red sandstone described 

 by Humboldt as occurring so extensively in the southern provinces. 



On ascending the Missouri frofti its junction with the Mississippi 



