126 CRETACEOUS AND TERTIARY FISH. 



isoceles triangle, ending in a moderate symphyseal beak. Outer 

 surface of mandibular concave medianly and convex above 

 (below damaged). Outer profile concave anteriorly, then sloping 

 up somewhat undulated and ending above convexly, below and 

 behind (damaged) apparently more or less convex. Inner sym- 

 physeal edge beveled rather short and deep and flattened, except 

 behind, where a slight convex ridge projects and continued back 

 as a groove along posterior inner edge. Inner surface of mandi- 

 bular below and behind symphysis very slightly concave above 

 and equally convex below, with several indistinct longitudinal 

 striae. Oral surface of beak well concave and posteriorly forms 

 plane sloping slightly inwards, equally slightly convex, edges not 

 elevated externally. Inner dental area largest, comprising whole 

 inner posterior surface, extending forward slightly before an- 

 terior dental surface as sharp angle along inner edge, and form- 

 ing deep undulation or loop just below anterior outer dental area. 

 Latter smallest of dental areas, rounded, and placed on com- 

 paratively level surface. Posterior outer dental area much longer 

 than anterior, close to edge, elongated and still closer to inner 

 dental area, only separated by a narrow level area. Lower sur* 

 face of mandibular exposing rather broad longitudinal area 

 marked with numerous even broadly lunate striae. Length 115 

 mm. 



Only the type described above have I been able to examine. 

 Cope had three other examples besides the type from Greensand 

 No. 5, near Hornerstown, in Monmouth County. He notes that 

 they showed the general peculiarities, as interrupted masticatory 

 surface, small external areas, anterior subround and opposite or 

 behind apex of very large inner. Narrowed beak forms an angle 

 with posterior part of jaw and penetrated by a laminar column 

 of little width. 



Formation and locality. This species is recorded as from the 

 Cretaceous marls of Burlington County and near Hornerstown 

 in Greensand No. 5. It is tentatively referred to the Horners- 

 town marl. 



