scHtJCHEET.] INDEX AND BIBLIOGRAPHY. 187 



Conchidium multicostatum Hall. Niagara (Sil.). 



Pentamerus miilticostatiis Hall, Geol. Survey Wisconsin ; Rep. Progress, 1860, 



p. 1 ;— Twentieth Rep. New York State Cab. Nat. Hist., 1867, p. 373, pi. 13, 



figs. 22-24. 

 Conchldium multicostatum Hall and Clarke, Pal. New^ York, VIII, Pt. II, 1895, 



pi. 64, fig. 6; pi. 66, fig. 10. 

 Loc. Wauwatosa and Waukesha, Wisconsin. 



Couchidium nettelrothi Hall and Clarke=C. kuighti. 



Conchidium nysius (Hall and Wliittield). Niagara (Sil.). 



Pentamerus nysius var. crassicosta Hall and Whitfield, Twenty-fourth Rep. New 



York State Cab. Nat. Hist., 1872, p. 184; — Twenty-seventh Rep. Ibidem, 



1875, pi. 10, figs, 4-7. — Nettelroth, Kentucky Fossil Shells, Mem. Kentucky 



Geol. Survey, 1889, p. 60, pi. 28, figs. 5-8. 

 Pentamerus nysius var. tenuicostatus Nettelroth, Ibidcn, 1889, p. 60. 

 Couchidium nysius Hall and Clarke, Pal. New York, VIII, Pt. II, 1893, p. 235, 



pi. 64, figs. 1, 8, 27. 

 Loc. Louisville, Kentucky. 

 Ohs. See C. tenuicostatum. 



Conchidium obsoletum Hall and Clarke. Niagara (Sil.). 



Couchidium obsoletum Hall and Clarke, Pal. New York, VIII, Pt. II, 1895, pi. 



67, figs. 8, 9. 

 Loc. Genoa, Ottawa County, Ohio. 



ConcMdium occidentale Hall. Guelph (Sil.). 



Pentamerus occidentalis Hall, Pal. New York, II, 1852, p. 341, pi. 79, figs. 1, 2.— 

 Billings,* Geol. Canada, 1863, p. 337, fig. 341. — Nicholson, Pal. Prov. Ontario, 

 1875, p. 67, fig. 35.— Whitfield, Geol. Wisconsin, IV, 1882, p. 314, pi. 17, fig. 10; 

 pi. 23, figs, 1, 2.— Hall and Clarke, Pal. New York, VIII, Pt. II, 1893, p. 239, 



Conchidium( ?) occidentalis Hall and Clarke, Ibidem, 1895, pi, 67, figs. 1-5. 



Loc. Gault and Guelph, Ontario ; Point St. Vital, Lake Huron ; Williamstown, 

 Wisconsin. 



Coiicliidium(?) salinense (Swallow). ''Base of Chemung-' (Dev.). 



Pentamerus salinensis Swallow, Trans. St. Louis Acad. Sci., I, 1860, p. 652. — 



Keyes, Geol. Survey Missouri, 'V, 1895, p. 104. 

 Loc. Moniteau County, Missouri. 

 Ohs. The geological horizon is probably Corniferous or Hamilton. 



Conchidium scoparium H'«,ll and Clarke, Guelph (Sil.). 



Conchidium scoparium Hall and Clarke, Pal. New York, VIII, Pt, II, 1895, pi. 



67, figs. 6, 7. 

 Log. Durham, Ontario. 



Conchidium tenuicostatum (Hall and Whitfield). Niagara (Sil.). 



Pentamerus nysius var. tenuicosta Hall and Whitfield, Twenty-fourth Rep. New 

 York State Cab. Nat. Hist., 1872, p. 184;— Twenty-seventh Rep. Ibidem, 

 1875, pi. 10, figs. 1-3. 



Pentamerus complanatus Nettelroth, Kentucky Fossil Shells, Mem. Kentucky 

 Geol. Survey, 1889, p. 53, pi. 27, figs. 14-16. 



Conchidium tenuicostatus Hall and Clarke, Pal. New York, VIII, Pt. II, 1893, 

 p. 235, pi. 64, figs. 3-5, 



Loc. Louisville, Kentucky, 



Ohs. P. nysius is described as consisting of two varieties. If these varieties are 

 species, as pointed out by Nettelroth, then P. nysius will be based upon and 

 supplant variety crassicosta, while variety tenuicosta must be elevated to 

 specific rank. P. complanatus Nettelroth, therefore, becomes a synonym for 

 C. tenuicostatum, as both are established upon the same specimens. 



