93 PALEONTOLOGY OF THE EUREKA DISTRICT. 



east of the Jackson mine; a little to the northeast of Adams Hill, and onr 

 ridge southwest of Wood Cone, Eureka District, Nevada. In the White 

 Pine District, Nevada, it was found in the central portion of the Pogonip 

 limestone on Pogonip Ridge. 



Genus ASAPHUS Brongniart. 



Asaphus Caribouensis, n. sp. 

 Plate xii, figs. 7, 7 a, 6. 



General form of the head semi-elliptical, moderately convex; glabella 

 expanding quite rapidly in front of the eyelobes and obtusely angular in 

 front; eyelobes situated back of a line uniting their anterior margins and. 

 the center of the glabella; postero-lateral limbs short and triangular in out- 

 line. The associated free cheek is a little longer than wide and with a dis- 

 tinctly marked border and genal spine 



The pygidise occurring in the same hand specimens have a rather 

 prominent medium lobe and smooth, depressed lateral lobes, without traces- 

 of segments on the latter. 



Formation and localities. Pogonip Group, in the lower portion asso- 

 ciated with the preceding species, and also in the upper beds at the west 

 base of Caribou Hill, Eureka District, Nevada. 



Asaphus ? curiosa Billings. 



Plate xii, fig. 15. 

 Asaphus ? curiom Billings, 1865. Pal. Foss., vol. i, p. 318, fig. 305. 



This curious pygidium, which is so closely allied to that described by 

 Mr. Billings under the above name, shows traces of annulations on the me- 

 dian lobe when the outer shell is removed. Three specimens were obtained, 

 but no associated parts of the head or thorax. 



Fragments of two other species of Asaphus occur in the upper layers 

 of the Pogonip Group. One from Caribou Hill has a broad, smooth, planu- 

 late pygidium with a very small and short median lobe, and is unlike any 

 species known from American strata, being allied to some forms, described 

 by Angelin, from Sweden. The other species is related to A. Caribouensis 



