302 Harris — Eocene Deposits of Maryland and Virginia. 



his own expression, belongs to a higher or "Buhrstone" hori- 

 zon. 



Practically the same conclusions were reiterated by Heilprin* 

 in a "Note on the Approximate Position of the Eocene De- 

 posits of Maryland," published in the Proceedings of the 

 Academy of Natural Sciences of Philadelphia, 1881. Conrad's 

 stratigraphic nomenclature he modernized to some extent and 

 used the term " Eo-lignitic " in place of Conrad's "Lignite 

 Formation. " 



It was not until 1886 that the typical section of American 

 marine Eocene, namely, that of Alabama was published. This 

 was given in Bulletin JSTo. 43 of the U. S. Geological Survey 

 by Smith and Johnson. In the same year also, appeard Bul- 

 letin No. 1 of the State survey of Alabama in which Aldrich 

 listed the known species from the various stages and sub-stages 

 of the series. Herein is found the clue to the special problem 

 in question, i. e., what horizon in the Alabama section does the 

 Eocene of Maryland and Virginia (Pamunkey formation of 

 Darton) represent. Whereas the Buhrstone and the section 

 on Bashia Creek furnish few or no characteristic Maryland 

 and Virginia Eocene species as neither Conrad nor Heilprin 

 were able to show although for some cause they believed all 

 should be relegated to practically the same horizon, the Bell's 

 Landing sub-stage including the Bell's Landing, Gregg's Land- 

 ing, and Nanafalia deposits do furnish such characteristic fos- 

 sils. During a recent visit to these localities I observed that 

 the material in which the fossils are imbedded is very similar 

 to that of the Virginia Eocene, while the fossiliferous zones 

 are widely separated by beds of fine dark lignitic clay. The 

 species obtained that are most telling as indices of horizon are 

 as follows : 



Dosiniopsis lenticularis Rogers ; found at Bell's Landing ; 

 also very abundant in the Maryland and Virginia (Pamunkey) 

 Eocene. A slight varietal form from the vicinity of Piscata- 

 way Creek and Ft. Washington has been named D. meeki by 

 Conrad. 



Cucullcea transversa Rogers ; common in the Gregg's Landing 

 bed and in Virginia, probably simply a small variety of C ono- 

 chela Rogers and C. gigantea Conrad. 



Venericardia plcmicosta, var. regia Con. ; common in all 

 members of the Bell's Landing sub-stage as well as in Virginia 

 and Maryland. 



Ostrea compressirostra Say ; abundant in the Bell's Landing 

 horizon of Alabama and in Maryland and Virginia. 



Turritella mortoni, var., postmortoni, nov var. ; very abund- 

 ant at Gregg's and Bell's Landing; rare among other T. mor- 



* Pp. 444-447. 



