14 
PALEONTOLOGY OF NEW YORK. 
PHACOPID^. 
P H A C 0 P S, Emmrich. 1839, 
Phacops cristata. 
PLATE VI, FIGS. 1-13, 16-29 ; and PLATE VIII a, FIGS. 1-1. 
Phacops cristata, Hall. Descr. New Sj^ecies of Fossils, etc., p. 67. 1861. 
Phacops hovibifrons, Hall. Descr. New Species of Fossils, etc., p. 67. 1861, 
Phacops cristata. Hall. Fifteenth Rept N. Y. State Cab. Nat. Hist., p. 95. 1862. 
Phacops bombifrons, Hall. Fifteenth Kept. N. Y. State Cab. Nat. Hist., p. 95. 1862. 
Phacops cristata. Hall. Illustrations of Devonian Fossils, pi. vi, tigs. 1-13, 16, 17. 1876. 
Phacops bombifrons. Hall. Illustrations of Devonian Fossils, pi. vi, figs. 18-29. 1876. 
General Form and Proportions. Outline elongate, sub-elliptical. Length to 
width as 1.7 to 1. Lateral margins sub-parallel. 
Surface depressed-convex, echinate along the axis. 
Cephalon broadly ovate or nearly semi-circular in outline; length to width as 
4 to 7. Frontal area obsolete, lateral area narrow, margins broadly thickened 
by doublure, and produced at the genal angles into short blunt spines, which 
are directed slightly upward and inward. Sub-marginal sulcus strong, ex¬ 
tending to within a short distance of the genal extremities, bearing on the 
lateral margins, behind the epistoma, ten or eleven crenulations which 
diminish in size backward. Epistoma comparatively narrow. 
Facial Sutures not observed. 
Glabella broad, convex, sub-pentagonal, tumid (generally flattened in ex¬ 
amples from the Schoharie grit), protuberant, extending for one-third its 
length beyond the frontal margin. In fiivorably preserved specimens, either 
of the external or internal surface, traces may be seen of the first and second 
pair of lateral furrows ; third lateral furrows deeply impressed but undefined, 
making the third or basal lobes of the glabella very obscure. Antero-lateral 
furrows may sometimes be discerned in front of the first pair of lateral fur- 
-rows, and parallel to the palpebral sulci. 
Occipital furrow broad and deep; occipital ring elevated and conspicuous. 
