6 PROCEEDINGS OF THE NATIONAL MUSEUM vol.82 



Central smooth areas surrounded by a concentric zone of promi- 

 nent radiating ribs, about 10 mm long and 1 mm wide, separated by 

 equally wide intervals. Ribbed area possessing granular surface 

 like the central one, but lacking the pores. 



The marginal region of the upper side (outside the ribbed area) 

 and the whole under surface composed of short (about 0.5 mm long), 

 straight or slightly curved, vertical, platelike spicules that form a 

 reticulate meshwork with irregular, circular, polygonal, and elongate 

 pores, averaging 0.5 mm in diameter. Where best preserved they 

 are fairly uniformly circular. Between them, in the middle of the 

 underside, are fairly evenly distributed monticules, about 2 mm apart 

 and 1.5 to 2.5 mm in diameter, circular in outline, slightly convex, 

 surrounded by radiating spicules, and often provided with a central 

 group of round Iniobs and depressions. 



One of these specimens was collected more than 10 years ago by 

 Dr. H. Justin Roddy, then at the Teachers College, Millersville, Pa., 

 and now at Franklin and Marshall College in Lancaster, Pa., while 

 the holotype was obtained by him in 1931. 



Horizon and locality. — ^Lower Cambrian, Kinzers formation {Olen- 

 ellus zone) : Loc. 12x, Fruitville. 3 miles north of Lancaster, Pa. 



Holotype and paratypes. — U.S.N.M. No. 85181. 



CAMPTOSTROMA RESSEKI, new species 



Plate 3, Figures 1-3 



Another fossil of similar outline and character — merely an impres- 

 sion in black Lower Cambrian slate from North Granville Bridge, 

 N. Y., found in the National Museum's collections — was later sent to 

 me for comparison with Camptostroma roddyi. 



The specimen is labeled "medusa imprint?," and indeed at first 

 glance it suggests a medusa more than anything else. The conclu- 

 sions, however, that were obtained in regard to G amptostroma and 

 the presence of a small portion of the original skeleton of the fossil 

 found in the center support the view that this fossil is actually con- 

 generic with C. roddyi. I shall therefore describe it as Campto- 

 stronna resseri. 



Description. — Hydrosoma disk shaped or lenticular, of circular 

 outline, about 7.5 cm in diameter. Central area of the side ex- 

 posed, somewhat elevated and surrounded by a ring of wedge- 

 shaped lobes with flat, smooth surfaces, about 20 mm long and 5 

 to 7 mm wide at the outer extremity. The outer margin is slightly 

 scalloped corresponding to the lobes. The small portion of the 

 body of the fossil in the center consists of a porous mass strongly 

 resembling slag, and obviously forming the interstitial filling of a 

 meshwork of irregular spicules such as forms the skeleton in the 

 genotype. 



