268 SYSTEMATIC PALEOXTOLOGY 



Family CLITAMBONITIDAE 



Genus SGENIDIUM Hall 



SCENIDIUM ANTHONENSE Sardeson 



Plate XLVII, Figs. 1-3 



Scenidium anthonensis Sardeson, 1892, Bull. Minnesota Acad. Nat. Sci., 



vol. iii, p. 333, pi. iv, fig. 7. 

 Scenidium halli Hall and Clarke, 1892, Pal. New York, vol. viii, pt. 1, p. 242, 



pi. viiA, figs. 33-39. 

 Scenidium anthonensis Winchell and Schuchert, 1893, Geol. Minnesota, 



vol. iii, p. 381, pi. xxx, figs. 20-23. 

 Scenidium anthonensis Weller, 1903, Geol. Surv. New Jersey, Pal., iii, 



p. 157, pi. x, figs. 5-7. 



Description. " Shell small, subsemi-circular in outline, the greatest 

 width along the hinge-line. Each valve marked by from 20 to 26 simple, 

 rounded plications. Pedicle valve subpyramidal, the beak erect; cardinal 

 area large, flat, broadly triangular, with a large delthyrium. Along the 

 median line a slight elevation or ill-defined fold is developed. In the 

 interior of the apical portion of the valve is a small spondylium. Brachial 

 valve depressed, convex, with a slight mesial sinus. The dimensions of 

 an average specimen arc : Length, 2.5 mm., and breadth, 5 mm." 

 Weller, 1903. 



Occurrence. CHAMBEKSBURG LIMESTONE (Nidulites bed). Wilson 

 and Pinesburg Station, Maryland. 



Black Eiver group of Minnesota, Iowa and New Jersey. 



Collections. Maryland Geological Survey, U. S. National Museum. 



SCENIDIUM ? MEROPE (Billings) 

 Plate L, Figs. 14-16 



Orthis merope Billings, 1865, Geol. Surv. Canada, Pal. Fossils, vol. i, p. 139, 



fig. 116. 

 Scenidium ? merope Hall and Clarke, ? 1892, Pal. New York, vol. viii, pt. 1, 



p. 242, pi. viiA, figs. 31, 32. 



Description,. Shell small, subpyramidal, somewhat semi-circular, with 

 a width to the hinge-line of 6 mm. and a length of 3 mm. ; cardinal angles 

 acute, from 60 to 70 ; exterior surface marked with 25 to 30 strong 



