484 CAMBKIAN BRACHIOPODA. 



distinguish it from lAngula attenuata Sowerby [Davidson, 1866, p. 44] and give a specific name 

 that will not lead to erroneous stratigraphic correlations. The Cambrian fauna of Sardinia is 

 so distinct from that of other localities and the stratigraphic succession of the subfauna is so 

 confused that I think it unwise to identify its species with described species unless the material 

 is so full and well preserved that there is no doubt of their specific identity. 

 The specific name was given in honor of Dr. J. G. Bornemann. 



Formation and locality. — Middle? Cambrian: (354) Yellowish-brown slates not far from, the buildings of Canal 

 Grande; (364a) grayish-white quartzitic sandstone in the valley of Guttui'u Sartu; (354b} yellowish sandstone with 

 Archxocyathus at Punta Pintau and elsewhere; all [Bornemann, 1891, p. 438] in the island of Sardinia, Italy. 



, LiNGTJLELLA BXJTTSI Walcott. 



V 



Plate XXIX, figures 4, 4a-b. 



Lingulella buttsi Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, pp. 70-71, PI. VIII, fig. 6. (Described and 

 discussed as below as a new species. Fig. 6 is copied in this monograph, PL XXIX, fig. 4.) 



General form elongate ovate, with the ventral valve bluntly acuminate and the dorsal valve 

 a little more rounded on the posterior margin. Both valves rather strongly convex. The great- 

 est convexity of the dorsal valve is at the umbo, and of the ventral valve along the central sec- 

 tion. A ventral valve 12 mm. in length has a convexity of 2 mm., and a dorsal valve 8 mm. 

 long arches 1.75 mm . above the plane of the margin. A narrow, median, slightly flattened, 

 almost concave space that extends from the apex to the front margin occurs on the dorsal 

 valve. The exterior surface of the shell is dull dark-bluish gray and the inner layers shiny 

 bluish black. The outer surface is marked by concentric striae and lines of growth with a few 

 indistinct radiating striae ; the striae on the dorsal valve bend sUghtly backward where they cross 

 the median, flattened space. The inner layers have many concentric striae, also numerous 

 fine radiating stiise. The shell is built up of several layers or lamellae, so as to be strong in the 

 umbonal region and thin toward the edges. 



The largest ventral valve in the collection has a length of 12 mm. and a maximum width 

 of 9.5 mm. at the anterior third of its length; a dorsal valve 10 mm. long has a width of 7 mm. 



A partly exfoliated ventral valve indicates the presence of a strong ridge on each side of 

 the visceral area somewhat similar to that in Lingulella acutangula (Roemer) (PI. XVII). 



Ohservations. — This fine shell has the general outline of the group of small shells of which 

 Lingulella ferruginea Salter is typical. It differs from them in its large size and strong shell. 

 All of the larger species of Lingulella are either more acuminate or broader in outline. 



The material was collected by Mr. Charles Butts, of the United States Geological Survey, 

 and I take pleasure in naming the species after him. 



Formation and locality. — Middle Cambrian: (90b) Conasauga limestone in cut on Louisville and Nashville 

 Eailroad, near Woodstock; and (90c) Conasauga limestone near Kimbrel; both in Bibb County, Alabama. 



Lingulella cania (Walcott). 



V 



Plate XXXV, figures 3, 3a-d. 



Obolus (Lingulepis) gregiva Walcott (in part) [not (Matthew)], 1901, Proc. U. S. Nat. Mus., vol. 23, p. 694. (Speci- 

 mens now referred to Lingulella cania are here mentioned as representing the young of Lingulella (Lingulepis) 

 gregiva.) 



Obolu.s (Lingulella) canius Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, pp. 610-611. (Described as below as a new 

 species.) 



Shell small. General form elongate oval, with the ventral valve slightly acuminate. In 

 both the ventral and dorsal valve the shell narrows posteriorly, the front being broadly rounded. 

 The convexity of the two valves is well marked, and it is nearly the same in each. 



Surface of the shell marked by fine concentric strise and a few lines of growth. When the 

 outer shell is exfoliated fine radiating striae cross the fine concentric striae. The shell appears 

 to be of moderate thickness and formed of several thin layers or lamellae. The largest ventral 

 valve in the collection has a length of 5 mm. ; width, 3 mm. ; and a dorsal valve 4 mm. in length 

 has a width of 2 mm. 



