CRUSTACEA. 27 



Phacops Cacapona. 



PLATE VIII, PIGS. 19 U. 

 Calymene bufo, Castelnad. Essai sur le Syst. Sil. de ['Amir. s ''pt , p. 21, pi, ii, figs. 1 I. 1843. 

 Phacops Cacapona. Hall. Descr. New Species i f Fo ils, etc., p. 68. 1861. 



Phacops Cacapona, Hall. Fifl th Rept. N. V. State Cab. Nat. Hisl . p. 91 



Phacops Cacapona, Hall. Illustrations of Devonian Fossils, pi. viii, figs. IS 23. 1876. 



The two specimens from which this species was originally described are inte- 

 rior and somewhat imperfect casts of enrolled individuals, retaining very few ol 

 the features which are essential in determining the value of closely allied species 

 of this genus. In general proportions they resemble Phacops rami, as that fossil 

 appears in the limestone layers of the Hamilton group, except that the glabella is 

 more protuberant and the glabellar furrows more strongly marked, and in these 

 features it approximates Phacops cristata. Whether the species belongs to either of 

 these two, or is valid in itself, cannot be definitively determined without the ac- 

 quisition of specimens retaining the test, the genal extremities and the pygidium. 

 The specimens described and figured by Castelnau(/or.e//.)as ( 'alymene bufo, Green, 

 were from the same locality as the type specimens of Phacops Cacapona. This author's 

 figures do not, however, assist in determining the specific value of his examples. 



Distribution. Hamilton group. Mouth of the Cacapon River, near its junc- 

 tion with the Potomac, Virginia. 



Phacops nupera. 



PLATE VIII, FIG. r,. 

 Calymene nupera, Hall. Geology of N. Y. Survey Fourth Geol. Dist., p. 262, fig. 116. 1S43. 

 Phacops nupera, Hall. Illustrations of Devonian Fossils, pi. viii, fig. 26. 187U. 



The type specimen of this species was found during the progress of the geo- 

 logical survey of the State in a loose block of sandstone, apparently of the age of 

 the Chemung sandstones, near the mouth of Chemung Creek, in Chemung county. 

 No other specimen is known to have been found since, and this is not satisfactorily 

 preserved for purposes of identification. In all apparent features it agrees with 

 Phacops rana of the Hamilton group, but the critical characters for distinguishing 

 the Devonian Phacopcs, viz. : the genal extremities, the cephalic doublure and 

 the pygidium, are not retained, and it is consequently impossible to determine 

 its specific value. The original designation is, therefore, retained, awaiting the 

 acquisition of material which may serve either to establish or discard it. 



Distribution. Chemung group. Chemung Creek, Chemung county. 



