90 PALEONTOLOGY OF THE EUREKA DISTRICT. 
indicating four coalesced segments, marked by pleural grooves and termi- 
nating in points that give a digitated margin to the pygidium. 
Surface apparently smooth. 
As all of these parts occur at one horizon and in the same layer, and 
no other large trilobite is associated with them, they undoubtedly belong to 
one species. 
Formation and localities—In the lower portion of the Pogonip Group, 
on the east slope of the ridge next east of the Hamburg Ridge, Eureka 
District, Nevada. 
Dicellocephalus inexpectans, n. sp. 
Plate i, fig. 10. 
Glabella quadrangular, moderately convex, lateral margins parallel, 
broadly rounded in front; surface marked by two pairs of slightly im- 
pressed glabellar furrows directed obliquely inward and backward; the 
occipital ring is of medium width, and the occipital furrow distinctly but 
not deeply marked; dorsal furrows clearly defined at the sides and front of 
the glabella; fixed cheeks very narrow, sloping rapidly away before and 
behind the palpebral lobe; palpebral lobes prominent and of medium size; 
frontal limb rather long and well extended laterally; a number of raised 
lines radiate from the front of the glabella to the frontal margin; frontal 
margin narrow, rounded; postero-lateral limbs unknown. The facial sutures 
pass very obligely inward from the anterior margin to the palpebral lobe, 
giving the front inclosed within them a campanulate form; curving around 
the palpebral lobes they pass outward on the postero-lateral limbs. 
Surface finely granulose. 
This species is associated in the same horizon with D. jinalis of this 
report. It was collected one year after the latter was described in MSS. 
It affords another illustration of a Cambrian type continuing into the Silu- 
rian and mingling with its fauna. 
Formation and localities—Same as D. jfinalis. 
