NO. 12 SPENCE SHALE AND ITS FAUNA RESSER IQ 



ELRATHIA RARA, n. sp. 



Plate 6, fig. 1 8 



This species is based on a single individual, consisting of the 

 ■cranidium and ly segments. Most of the cranidium is exfoliated, and 

 shows strong striations on the preglabellar area. A narrow, straight 

 rim is demarcated. 



Locality 55c. 



Holotype. — U.S.N.AL no. 96541. 



ELRATHINA Resser, 1937 

 ELRATHINA OFFULA, n. sp. 



Plate 2, figs. 13, 14 



This genus and species is represented by only a few cranidia. The 

 illustrations show the relative proportion of the several parts, the 

 characteristic constriction of brim width, and the slightly concave 

 brim, with the rim only weakly defined. Eyes are rather small. 



Locality 55c. 



Holotype and paratypc. — -U.S.N.M. no. 96510. 



EHMANIELLA Resser, 1937 

 EHMANIELLA QUADRANS (Hall and Whitfield) 



Plate 6, figs. 28-32 



Crepiccphahisf (Logancllus) quadrans Hall and Whitfield, U. S. Geol. Expl. 



40th Par., vol, 4, p. 238, pi. 2, figs. 11-13, 1877. 

 Ptychoparia qimdrans Walcott, U. S. Geol. Surv. Bull. 30, p. 199, pi. 29, 



figs. 4, 4a, b, 1886; Smithsonian Misc. Coll., vol. 64, p. 204, 1916. 

 Ehmaniella quadrans Resser, Smithsonian Misc. Coll., vol. 95, no. 22, p. 10, 1937. 



Localities 20x, 55e, and 54L. 



Holotype and paratypes. — U.S.N.M. no. 15432; plesiotype, no. 



96539- 



CLAPPASPIS Deiss, 1939 



The genotype, C. typica Deiss, comes from the Pentagon shale of 

 Lewis and Clark Range, Montana. Average size and shape, normal 

 development of eye lines and furrows, and eyes situated slightly be- 

 hind the middle of the head, characterize the genus. All species are 

 evidently ornamented by some sort of granulated surface. Deiss did 

 not have any entire individuals and so could not illustrate the thorax. 

 Several Spence shale individuals have 14 thoracic segments. 



Five species in the Spence shale are referred to Clap pas pis. 



