746 CAMBRIAN BRACHIOPODA. 



from maceration and flattening out of the surface characters by compression. The interior of 

 the shell appears to have been covered by minute punctse. 



The largest specimen of the collection has a transverse diameter of 14 mm. The average 

 siae of the ventral valve is about 8 mm. in height by 8 mm. in width. 



Cardinal area about one-fifth the height of the shell. It is marked by transverse strise of 

 growth that cross it parallel to its base. Delthyrium rather broad. No traces of the deltid- 

 ium have been observed. Cardinal area of the dorsal valve short. It is divided midway by 

 a strong delthyrium. Notlung is known of the interior characters except the presence of a short 

 crura in the dorsal valve. 



Ohservations . — This shell occurs quite abundantly in the very fine, buff-colored, argilla- 

 ceous shales of the Coosa Valley Cambrian section. There is some doubt as to its surface char- 

 acters, as only one specimen found m the same beds has traces of radiating striae, and these 

 may be from the interior radiating fines. All others appear to be nearly smooth. Its strongest 

 character is the extension of the cardinal angle. Owing to the imperfection of the material the 

 generic reference is doubtful. 



The species was anomalous while under BiUingseJla, to wliich it was first referred, hence 

 the specific name. 



Formation and locality. — Middle Cambrian: (90) Conasauga ("Coosa") shale, on Ed-n-ards farm, near Craigs 

 Mountain, about 10 miles (16.1 km.) southeast of Center, Cherokee County, Alabama. 



WiMANELLA HAELANENSIS (Walcott) . 

 Plate LXXXVII, figures 5, 5a-d. 



Billingsella harlantnsis Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 236. (Characterized and discussed as below 

 as a new species.) 



The general form and convexity of this shell is similar to that of Billingsella plicateUa 

 Walcott. It difl'ers in having a nearly smooth surface marked only by fine concentric striae 

 and a few traces of narrow, sharp radiating costae. The interior of the ventral vah^e has very 

 strong main vascular sinuses and a deep, sharply defined, tripartite umbonal area opposite the 

 delthyrium; the tripartite area is much like that in Billingsella coloradoensis (Shumard) and 

 B. exporrecta (Linnarsson) . The main vascular sinuses pass directly back across the ridge in 

 front of the tripartite area and occupy the two lateral divisions of the area. The interior of the 

 dorsal valve represented in figure 5a shows an abnormal arrangement of the vascular markings 

 and muscle scars. 



The specific name is derived from Harlan Knob, Tennessee. 



Formation and locality. — Middle Cambrian: (107) Limestone in Bull Run, northwest of Copper Ridge [Keith, 

 1896b, areal geology sheet], 11 miles (17.6 km.) northwest of Knoxville, Knox County; and (121) Rogersville shale, 

 roadjxist east of Harlan Knob, 4 miles {6.4 hra.) northeast of Rogersville {Keith, 1905, areal geology sheet], Hawkins County; 

 both in Tennessee. 



WiMANELLA INYOENSIS Walcott. 



Text figures 63A-B, page 747. 



Wimanella inyoensis Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, p. 99, PI. X, fig. 4. (Described as below 

 as a new species. Fig. 4 is copied in this monograph as fig, 63A.) 



This species is represented by numerous specimens in the form of casts in a calcareous 

 sandstone. All of the shells are more or less compressed and distorted. Some of those best 

 preserved indicate that the general outline was transverse. A specimen 6 mm. in length has a 

 width of 7 mm. The two specimens illustrated (figs. 63A and 63B) occur on the same fragment 

 of rock and illustrate fairly well the difference in outline; it may be that figure 63A is the 

 narrow ventral valve and figure 63B the. broader dorsal valve. 



