Fossil Plants. 



31 



cunx ; grooves half an inch in width, two-eighths deep ; disks nearly 

 filling the width of the groove, a little raised, and depressed at one 

 side ; distance equal to the diameter of the disks. 



Observations. — A most beautiful and perfect impression, about 

 fifteen inches in length ; the original trunk, of which this is only a 

 segment, must have been more than a foot in diameter, and many 

 feet in length. In fine grained sandstone, at Mariner's Mills, and 

 named for that locality. I received also a beautiful cast of Cala- 

 mites columnare, remarkable for the size and depth of the columns, 

 from Dr. K., finely impressed in red sandstone, from a locality some 

 miles north of this spot. (Fig. 6.) 



Fie. 6. Fio:. 7. 



Half size. 



FicoiDiTES scABRosus. Specific Character and Description.— ' 

 Cicatrices approximate ; arranged spirally ; spines small, stem cyl- 

 indrical ; one inch and a half in diameter, up to four inches ; length 

 unknown. 



Observations. — ^When taken from the sandstone rock on the Maho- 

 ning River, the surface was coated with bituminous matter. This fossil 

 plant much resembles some of the recent species of Cactus, and was 

 probably of the same succulent growth, and coated with spines. I 

 have several specimens of various sizes, from half an inch to four 

 inches in diameter. They are all sandstone casts. Same locality, 

 (Fig. 7.) 



