NO. 5 CAMBRIAN TRILOBITES 395 



dium has a narrow, convex axial lobe with seven to eight not very 

 strongly defined rings that extend obliquely across the pleural lobes 

 as flat segments separated by narrow, shallow furrows ; the doublure 

 is broad (fig. if) and finely striated. 



Surface with fine, irregular granules set very close to each other 

 and sometimes with a tendency to follow irregular lines that suggest 

 that the granulation results from the breaking up of fine ridges. 



The largest dorsal shield has a length of 43 mm. 



Cephalon 13 mm. 



Thorax 19 " 



Pygidium 11 " 



Width of thorax 20 " 



Two enrolled specimens (see fig. ih) show that the animal rolled 

 up very much as in genera of the Asaphidae, Proteidae, etc. 



This species is one of the most abundant of those occurring on the 

 siliceous nodules of the Conasauga shales. It is associated with a 

 large and varied fauna of a Middle Cambrian facies. One of the 

 associated species, A. (B.) paula, is somewhat similar in form but 

 dififers in details of the cranidium and pygidium. 



Formation and locality. — Middle Cambrian: (gox) Conasauga 

 formation; in and attached to the outer surface of siliceous nodules 

 in a dark argillaceous shale of the lower Conasauga formation ; 3 

 miles (4.8 km.) east of Center, near Blaine, Coosa Valley, Cherokee 

 County, Alabama. 



Also (567) fine, arenaceous, buff-colored shales; 1.75 miles (2.8 

 km.) southwest of Greenback, on the railroad just north of wagon- 

 road crossing, Loudon County, Tennessee. 



ASAPHISCUS (BLAINIA) PAULA, new species 

 Plate 62, figs. 2, 2a-b 



This species has the same general characters of ^. (B.) gregarius, 

 such as form, nine segments in thorax, finely granulated surface, and 

 size. It differs in outline of glabella and smaller palpebral lobes of 

 cranidium, and the pygidium is quite dissimilar in details as may be 

 seen by comparing figures la, if, ig of plate 62 with figures 2, 2a. 

 The same comparison may be extended to A. (B.) glabra (pi. 63, 

 figs. I, la, lb). 



The largest dorsal shield has a length of 45 mm. 



Formation and locality. — Middle Cambrian: (gox) Conasauga 

 formation; in and attached to the outer surface of siliceous nodules 

 in a dark argillaceous shale of the lower Conasauga formation ; 3 



