105 



to the tertiary period, while the vertebrata are considered by Dr. Leidy 

 to belong to Wealden types and allied to those forms, discovered by 

 Dr. Mantell, in the Wealden strata of England. With evidence so 

 conflicting before us, it will be necessary to make a second exploration 

 of that region before we can come to any positive conclusion as t3 its 

 age. The following section, in descending order, will represent the 

 different beds with sufficient accuracy and detail for our present 

 purpose. 



Section of fresh water and estuary deposits near the mouth of Judith river. 



B. 



D. 



E. 



F. 



G. 



80 feet..! Yellow arenaceous marl passing downwards into gray grit, with small 

 seams uf lignite ; contains great numbers of Ostrea sublrig<maUs9, Oyrma 

 I occidentalis, Melania convexa, &c. 



10 feet.. 



80 feet. 



20 feet. 



100 feet.- 



25 feet.. 



100 feet.. 



Impure lignite, containing much sand, 

 wood. 



Osirea siiltrigonalis ? and silicified 



Alternations of sand and clay, witli particles of lignite ; also reddish 

 argillaceous concretions with a few saurian teeth, and fresh water 

 shells. 



Alternate strata of sand and clay, with impure lignite and silicified wood 

 in a good state of preservation. 



Variable bed, consisting of alternations of sand and clay with large con- 

 cretions containing great numbers of Melania, Paludina, Helix, Flanorbis, 

 Oyclas, &c. , associated with saurian remains resembling the Iguanodon. 

 and Megahsaurus, Trionyx, &c. 



Alternations of impure lignite and yellowish-brown clay, the latter con- 

 taining great numbers of Unio, Paludina, Melania, Oyclas, and the fresh 

 remains referred by Dr. Leidy to the genus Lepidotus. 



Ferruginous sand and clay, having in upper part a seam three or four 

 inches in thickness, nearly made up of shells of Unio. Lower part 

 ferruginous and coarse gray grit, with a seam near the base entirely 

 composed of remains of Unio Danai, U. Dewyi, and U. subspatulata. 



