80 Nor 111 American 



P^'gidium paraboloid in outline, liiglil}' convex, abruptly so at the sides 

 and posteriorly. Axial lobe forming a little less than \ of the entire width, 

 and reaching nearl}' to the posterior margin, rounded and strongly elevated 

 throughout ; gradually tapering posteriorly and narrowly rounded at the 

 extremity : marked by from 15 to 17 annulations in different individuals, 

 exclusive of the anterior articulating ring. Lateral lobes well marked, very 

 convex, slightly flattened near the axis, but very abrupt at the sides and be- 

 hind ; marked b}^ from 14 to 16 very sharply elevated angular ribs, which 

 occupy the entire border, extending beyond the end of the axial lobe, and 

 reaching almost to the margin, leaving onl}' a narrow plain space at the 

 edge. The surface of the annulations is marked by a series of small nodes, 

 or pustules, along their crests, arranged in four longitudinal rows on the 

 axial rings, and an indelinite number, closel}' arranged, occur on those of 

 the lateral lobes." 



The species^ in some of its features, resembles Proetus macro- 

 ceplialii8, Hall, of the shales of the Hamilton group of Xew 

 York, especially in the markings of the pygidium, but it differs 

 in the more elongate form and number of ribs of this part, while 

 the glabella is proportionately narrower and the sides more nearly 

 parallel ; the fixed cheeks and anterior border are narrower, and 

 the movable cheeks terminate in spines, which is not the case 

 with that one. The surface of the glabella and head is also des- 

 titute of the strong pustules wdiich characterize that species. 



Geological 2^osition and locality . — AYaverly group at Ogden, 

 Logan Canon, Wahsatch Kange, and Dry Caiion, Oquirrh Mount- 

 ains, Utah. 



PROETUS TENNESSEENSIS, Winchell. 



PMllipsia Tennesseensis. Winchell, 1869, Geol. Tennessee, p. 445. 

 AV"e subjoin the original description : 



" Glabella prominent, indented by a small round, depressed postero-lateral 

 lobe, and isolated by a deep occipital furrow, from a prominent occipital 

 ring which extends, narrowing in width and curving backwards, entirely 

 across the border, fading out toward the short, acute genal angle. Border 

 concave, bounded by a prominent ridge, outside of which is a linear groove 

 limited peripherally by a sharp elevated, delicate linear margin. Surface 

 of the glabella, accessory lobe and neck-ring covered with fine unequal 

 granulations ; a row of granules along the ridge of the border. Pygidium 

 broadly rounded, nearly twice as long as broad, apparently depressed ; axis 



