NO. 5 CAMBRIAN TRILOBITES 4OI 



punctce ; the inner surface of the depressed axial lobe of the pygidium 

 is marked by from 14 to 16 narrow rings that are extended rather 

 faintly across the pleural lobes. 



The largest cranidium has a length of 12 mm. and pygidium of 

 1 1 mm. 



Maryvillia avion differs from M. ariston in the form of the frontal 

 limb and border of the cranidium and the shape of the associated 

 pygidium. Both species occur in the Maryville limestone but not at 

 the same localities. 



Formation and locality. — Upper Cambrian: (123b) Maryville 

 limestone near its top beneath the Nolichucky shale; 0.5 mile (0.8 

 km.) east of depot on left of railway in wagon road, Rogersville, 

 Hawkins County; U19) beneath Nolichucky shale, on Cub Creek, 

 1.5 miles (2.4 km.) southeast of Morristown, Hamblen County; and 

 (107c) west base of Copper Ridge; 11 miles (17.7 km.) northwest 

 of Knoxville, Knox County, all in Tennessee. 



MARYVILLIA ARISTON, new species 



Plate 64, figs. 5, 50 



Maryvillia ariston is known by its cranidium and a type of 

 pygidium that is associated with it. It has the general characters of 

 M. arion, but differs in the form of the combined frontal limb and 

 border, and its associated pygidium is more elongate ; the latter has 

 16 or more rings in its axial lobe and nearly smooth pleural lobes. 



Surface of outer test finely pitted, apparently nearly punctate; 

 inner surface of test finely granulated. 



The largest cranidium has a length of 11 mm. and the pygidium 

 13 mm. 



Formation and locality. — Upper Cambrian: (120) Maryville 

 limestone: north of Bays Aloimtain, 2 to 3 miles (3.2 to 4.8 km.) 

 south of New Market, Jefferson County, 18 miles (28.6 km.) east- 

 northeast of Knoxville; and (126a) east side of Gap Creek section, 

 10 miles (16 km.) east of Knoxville, Knox County, both in Ten- 

 nessee. 



Family OLENID^ Burmeister 

 MARJUMIA, new genus 



This genus appears to unite characters found in several genera. 

 The cephalon is essentially that of Asaphiscus, the thorax that of 

 Ptychoparia, and the pygidium that of several genera of the Olenids, 

 such as Peltura scarabccoides Wahlenberg and Parabolina megalops 

 TMoberg. 



