CAMBRIAX TRILOBITES — WALCOTT 35 



The surface markings of this species are much like those of N. 

 superhus and N. inflatus, but very much finer. On a cranidium ii 

 mm. in length the surface appears smooth, except under a strong 

 lens. 



Formation and Locality. — Middle Cambrian: 1,895-2,140 feet 

 (605-653.8 m.) below the Upper Cambrian and about 2,000 feet 

 (609.6 m.) above the beds containing Zacaiithoides typicalis Walcott 

 and Bathyuriscus howelli Walcott, the horizon which is correlated 

 with the horizon carrying Neolenus serratus (Rominger) in British 

 Columbia,^ in thin-bedded limestones of the Marjum formation, in 

 ridge on east side of Wheeler Amphitheater, east of Antelope 

 Springs, House Range, Millard County, Utah, U. S. A. 



NEOLENUS INTERMEDIUS PUGIO, new variety 



Plate 6, Figures 8, 9 



This variety is founded on four specimens of a pygidium that has 

 four rings and a terminal segment in the axial lobe, four marginal 

 spines on each side and three clearly defined anchylosed pleural 

 segments marked by oblique pleural furrows. A specimen 11 mm. 

 in length has a width at the front of 36 mm. The axial lobe has a 

 width of 5 mm. at the first segment and 3 mm. at the terminal 

 segment. 



This variety differs from A^. intermedins in having four instead 

 of five marginal spines on each side of the pygidium, four axial 

 rings instead of five and a shorter terminal section to the axial lobe. 

 A fragment of the outer surface shows it to have been of the same 

 type as that of A^ superhus. 



Formation and Locality. — Middle Cambrian: 1,895-2,140 feet 

 (605-653.8 m.) below the Upper Cambrian and about 2,000 feet 

 (609.6 m.) above the beds containing Zacanthoides typicalis 

 Walcott and Bathyuriscus howelli Walcott, the horizon which is 

 correlated with the horizon carrying Neolenus serratus (Rominger) 

 in British Columbia,^ in thin-bedded limestones of the Marjum 

 formation, in ridge on east side of Wheeler Amphitheater, east of 

 Antelope Springs, House Range, Millard County, Utah, U. S. A. 



^ This British Columbia horizon is given in detail in the Formation and 

 locality of Bnrlingia hectori. 



