NO. 3 CAMBRIAN TRILOBITES 21 5 



seg^ments, and pygidium. The associated pygidium is much like 

 that of C. tripunctatiis magnispinus. 



With the exception of the great occipital spine, C. thoosa is closely 

 related to C. tripunctatiis magnispinus. The pygidium referred to 

 the latter is proportionally narrower, but the i:)ostero-lateral spines 

 are similar. 



This species occurs in the upi)er part of the Conasauga shales in 

 northeastern Alabama, the Maryville limestone of eastern Tennessee, 

 and the Honaker limestone of western Virginia. 



Formation and locality. — Upper Cambrian: (125a) Maryville 

 limestone ; north side of Big Creek below Harlans mill, 4 miles 

 (6.4 km.) northeast of Rogersville; (125) about 50 feet below 125a; 

 (123b) upper beds of Maryville limestone, 0.5 mile (0.8 km.) east 

 of Rogersville railway depot on left of railway, in wagon road, 

 Hawkins County; (107) Bull Run Ridge, northwest of Copper 

 Ridge, II miles (17.6 km.) northwest of Knoxville ; (126a) east 

 side of Gap Creek section, 10 miles ( 16 km.) east of Knoxville, Knox 

 County; (119) beneath Nolichucky shale on Cub Creek, 1.5 miles 

 (2.4 km.) southeast of Morristown, Hamblen County; (120) north 

 of Bays Mountain on Beaver Creek, Sevier County, 18 miles (28.8 

 km.) east-northeast of Knoxville; (ii8a) Bird Bridge road, 1.5 

 miles (2.4 km.) south, and (117c) 5 miles (8 km.) southeast of 

 Greeneville, Greene County, all above in Maryville limestone of 

 Tennessee. 



Also (119a) Honaker (:= Maryville) limestone, 3 miles (4.8 km.) 

 east of Greendale, Washington County, Virginia. 



Also (145a) Conasauga shale; upper part of shale beneath Knox 

 dolomite; i mile (1.6 km.) east of Gaylesville ; also (91) Cedar 

 Bluff, both in Cherokee County ; and (3586) Conasauga shale, oppo- 

 site car barn, city of Birmingham, Jefferson County, all in Alabama. 



And (358f) Conasauga formation; limestone in shales, west of 

 Red Clay, Whitfield County, Georgia. 



CREPICEPHALUS TRIPUNCTATUS (Whitfield) 



Plate 33, figs. I, la-b 



Arionellus tripunctatus Whitfield, 1876, Rept. Reconnaissance from Car- 

 roll, Montana Terr., on the Upper Missouri, to the Yellowstone National 

 Park (Ludlow), p. 141, pi. i, figs. 3-5. (Original description and 

 illustrations.) 



Not Crepicephalus tcxanus (Shumard) Walcott, 1899, Monogr. No. 32, U. S. 

 Geol. Survey, p. 460. (Refers Arionellus tripunctatus Whitfield to 

 C. texanus (Shumard).) 



