GEOLOGICAL SOCIETY OF PENNSYLVANIA. 



321 



reminded us of those of the Portland rock. We traced 

 these conglomerate and lignite beds to the James river, 

 where, near Richmond, they overlie, as at Fredericks- 

 burg, the almost vertical primitive rocks. 



Over the coarser conglomerates of Fredericksburg are 

 others in which lignites, both silicified and in the state 

 of charcoal as well as in casts, are plentiful. Above 

 them, in numerous laminae and seams of bluish argillo- 

 silicious soft shale, resembling marl, but without lime, 

 occur several species of plants. The sedimentary char- 

 acter of these finer beds attests the slow and tranquil 

 circumstances attending their deposition, and affords 

 evidence of a prolongation of time adequate to the re- 

 peated renewal of vegetation on their successive sur- 

 faces. 



Our attention was first directed to these plants by Mr 

 F. Shepherd, who at our request furnished the Geologi- 

 cal Society with specimens. We observed no traces of 

 moUusca or animal exuviae among these elegant lignites. 

 In deposits of this character they may be expected, and 

 when found will materially assist in determining the 

 geological age of these rocks. 



Over the argillaceous beds are others of fine white 

 grit abounding in long stems of succulent plants resem- 

 bling flags. They are frequently in the form of hollow 

 casts, which, near the surface, are filled or penetrated 

 by the roots and fibres of existing vegetables. They 

 are perhaps allied to 



Lycopodiolithes? PL 19, Jig. 2. 



They exhibit no scales nor leaves. The longitudinal 

 elevations or striae are not prominent or distinct, nor are 

 they uniformly disposed on the surface of such speci- 

 mens as have reached us, whiieh occasions the more 

 hesitation in naming the genus of this plant. 



1—2 Q 



