354 SYSTEMATIC PALEONTOLOGY 



striae. Neck ring nearly flat, depressed, with a central tubercle ; occipital 

 furrow distinct, nearly straight. Sutures begin at the anterolateral angles 

 of the margin, extend in the direction of the second glabellar lobe to near 

 the glabella, and then curve backward." Euedemann, 1901. 



This species was based upon two small cranidia, both of which are 

 illustrated in the present report. The material here identified with 

 C. matutina consists of imperfect cranidia only, so that nothing further 

 can be added to the specific description. 



Occurrence. MAETINSBURG SHALE (Sinuites bed). Chambersburg, 

 Pennsylvania. Eysedorph conglomerate at base of Trenton, Kensselaer 

 County, New York. 



Collection. U. S. National Museum. 



Family LICHADIDAE 



Genus AMPHILIGHAS Raymond 



AMPHILICHAS TRENTONENSIS (Conrad) 



Plate LI, Figs. 8-10 



Asaphus f Trentonensis Conrad, 1842, Jour. Acad. Nat. Sci. Philadelphia, 



vol. viii, p. 277, pi. xvi, fig. 16. 

 Platynotus trentonensis Hall, 1847, Pal. New York, vol. i, p. 235, pi. Ixiv, 



figs. la-d. 

 Platymetopus trentonensis Weller, 1903, Geol. Surv. New Jersey, Pal., 



vol. iii, p. 200, pi. xv, figs. 17-19. 



Description. " Head ventricose, the curve along the median line from 

 the posterior to the anterior margins being very nearly a semicircle, 

 sub-semicircular in outline, attaining a breadth of 35 or 40 mm. The 

 glabella very large, occupying nearly the entire breadth of the cranidium, 

 strongly protuberant in front; with a single pair of glabellar furrows, 

 which originate at the anterior, lateral margins, and, after curving 

 inward, then backward and then slightly outward again, forming some- 

 thing more than a semicircle, they join the occipital furrow, dividing the 

 glabella into three lobes; the frontal or median lobe is broad in front, 

 becoming narrower posteriorly to a point back of the middle of the head, 



