Maryland Geological Survey 497 



areas small, nearly circular, but slightly elongate parallel to the longer 

 axis of the protuberances upon which they are situated. 



The description is from two specimens belonging to the U. S. National 

 Museum from near Franklin, Pendleton County, West Virginia. One 

 shows the genal angles well, but neither has the anterior extremity of the 

 cephalon. So far as the writer knows these two specimens and a fragment 

 in the New York State Museum are the only specimens of the cephalon 

 of this species yet discovered. 



Occurrence. — Oriskany Formation, Eidgely Member. Knobly 

 Mountain near Cumberland, Maryland ; opposite Franklin, West Virginia. 



Collections. — Maryland Geological Survey, U. S. National Museum. 



[Ohern.] 

 Family PHACOPIDAE 



Genus PHACOPS Emmrich 



PiiAcops logani Hall 



Plate XCI, Figs. 1-4 



Phacops logani Hall, 1859, Nat. Hist. N. Y., Pal., vol. iii, p. 353, pi. Ixxiii, figs. 



15-25, 1861. 

 Phacops logani Weller, 1903, Pal. N. J., vol. iii, p. 231, pi. xl, figs. 3, 4. 



Description. — " General form elliptical. Head semicircular in outline, 

 broadly concave above, with the posterior angles curved and declining 

 more abruptly. Glabella somewhat pentagonal ; length and greatest breadth 

 nearly in the proportion of three to four ; very prominent in front, project- 

 ing beyond the rudimentary frontal limb, which becomes more developed 

 on each side, and below which is a defined groove, marking the limits of the 

 lower side of the cephalic test. Upper surface convex, gibbous in front, 

 having two pairs of transverse grooves, the middle and posterior ones of 

 which are but faintly defined ; while the third or anterior ones, extending 

 from the inner angle of the eye backwards, and a little inwards, are 

 scarcely conspicuous, and, on many specimens, not observable. First 

 annular furrow strongly defined, and sometimes with a small tubercle at 

 the summit : first or intercalated annulation narrow and well defined, and 

 terminated at each extremity by a strong oblong tubercle, which is wider 

 than the annulations, and usually marked by two pustules at the summit, 

 one on each side of the center. Occipital furrow wider and more strongly 



