698 SYSTEMATIC PALEONTOLOGY 



on the other side of the triangular pit, a very short, trigonal cardinal, 

 feebly sulcated longitudinally; anterior and posterior laterals subequal, 

 symmetrically placed with respect to the umbones. double, more elevated 

 medially than toward the extremities ; two cardinals developed in the right 

 valve, the anterior short, thin, and laminar, the posterior placed directly 

 beneath the umbones, short but stout and broadly sulcate ; dorsal margins 

 bevelled to function as laterals but no true laterals developed ; muscle scars 

 rather large but obscure ; pallial sinus very broad, reaching approximately 

 to the median vertical not confluent with the pallial line. 



The species differs from Tellinimera eborea Conrad, which it super- 

 ficially resembles, in the more nearly equilateral outline due to the rela- 

 tively shorter and more angular anterior end of the latter. It differs, 

 furthermore, in the absence of the sharp, concentric striations which char- 

 acterize T. eborea. 



Occurrence. MONMOUTH FOKMATION. Brightseat, Brooks estate near 

 Seat Pleasant, Friendly, 1 mile west of Friendly, McNeys Corners, and 

 2 miles southwest of Oxon Hill, Prince George's County. 



Collections. Maryland Geological Survey, Philadelphia Academy of 

 Natural Sciences, New Jersey Geological Survey, U. S. National Museum. 



Outside Distribution. Matawan Formation. Woodbury clay, New 

 Jersey. Ripley Formation. Exogyra costata zone, Quitman County, 

 Georgia; Eufaula, Alabama; Union and Tippah counties, Mississippi. 

 Extreme top of zone, Pataula Creek, Georgia ; Chattahoochee River, Ala- 

 bama. 



Genus LINEARIA Conrad 

 [Jour. Acad. Nat. Sci., Phila., 2d ser., vol. iv, 1860, p. 279] 



Type. Linearia metastriata Conrad. 



" Oval or oblong ; cardinal teeth in the left valve two, the anterior one 

 elongated, very oblique, the other under the apex small and bifid. "- 

 Conrad, 1860. 



" The hinge shows two small, diverging, nearly equal teeth, directed 

 obliquely forward, the anterior one very oblique; and two rather long 



Etymology: Linearis, lineated. 



