NO, 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 111 



Length of largest cranidium 6 mm. Length of pygidium 3.5 mm., 

 width 7.5 mm. 



Discussion. — This species cannot be given a satisfactory generic 

 assignment. The cranidium differs from typical Modocia in the lack of 

 a convex anterior border, horizontal rather than downsloping palpe- 

 bral area, more posterior position of the eyes, and parallel-sided rather 

 than tapered posterior area. In all these features it closely resembles 

 cranidia of Marjumia typa. However, if the pygidium is correctly as- 

 signed, it is rather indicative of Modocia; spinose pygidia of the Mar- 

 jumia type were not recovered from the Maryville formation. 



Occurrence. — The type locaHty is U.S.N.M. 123a, near Rogersville. 

 Also collected by the author in the same area at localities cnc/2 to 

 cnc/5. The species belongs to the lower Cedaria zone faunule of the 

 uppermost Maryville limestone. 



Types.— Roloiy^e: U.S.N.M. 62819. Plesiotypes: U.S.N.M. 144- 

 72-^^-6. 



Genus LOXOPARIA Rasetti, new genus 



Description. — Cranidium subtrapezoidal, moderately convex. Gla- 

 bella moderately convex, unfurrowed, rising above the cheeks, with 

 slightly concave side outline, subtruncate in front, reaching the border. 

 Occipital furrow well marked ; occipital ring extended into spine. 

 Frontal area flat, consisting only of border ; border furrow present at 

 the sides, merging with axial furrow medially. Palpebral area some- 

 what over half the glabellar width, convex, downsloping ; ocular ridges 

 barely distinct, strongly slanted ; palpebral lobes short and narrow, in- 

 conspicuous, situated in advance of glabellar midpoint. Anterior sec- 

 tions of facial sutures directed forward from palpebral lobes, curving 

 inward ; anterior angles of cranidium widely rounded. Posterior sec- 

 tion of facial suture directed outward and backward, fairly straight for 

 half its course, then curving backward and finally somewhat inward. 

 Posterior area of fixed cheeks large, downsloping, extending back- 

 ward much farther than glabella, sharply pointed. Furrow on posterior 

 area deep, first directed outward and then curving forward ; posterior 

 margin of posterior area straight, strongly slanted outward and back- 

 ward. 



Type species. — Loxoparia obliqua Rasetti, n. sp. 



Discussion. — The shape of the glabella and frontal area are sug- 

 gestive of Llanoaspis and related forms ; however, the characters of 

 the palpebral area, palpebral lobes, and course of the posterior section 

 of the facial sutures are radically different. The affinities of this tri- 

 lobite are obscure. 



Occurrence. — Upper Cambrian (Cedaria zone) of the southern Ap- 

 palachians. 



