3/0 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 57 



Dikeloccplialus ininiiesotensis Owen, 1852, Rept. Geol. Survey Wis., Iowa, 

 and Minn., p. 574, pi. i, figs, i, 2; pi. la, figs. 3, 6. (Description and 

 illustrations of species. Fig. 10, pi. i, is now referred to D. crassimar- 

 ginatus.) 



Ogygia minnesoteiisis (Owen), Chapman, 1856, Canadian Journ., new ser., 

 Vol. I, p. 275. (Refers species to Ogygia.) 



Dikelocepfialus minncsotensis Owen, ^Mackie, 1859, The Geologist (Lon- 

 don), Vol. 2, p. 189, fig. 4. (Text figure of Owen's restoration of the 

 species.) 



Dikclocephalus minnesoteiisis Owen, Hall, 1862, Rept. Geol. Survey Wis- 

 consin, Vol. I, p. 22, figs. I, 2. (Illustrates a cranidium and a pygidium.) 



Dikelocephalus minnesoteiisis Owen, Hall, 1863, Rept. Geol. Survey Wiscon- 

 sin, p. 138, pi. 9, figs. 5-10; pi. 10, figs. 10-12; pi. II, figs. I, 3, and 4, 

 (Species described and illustrated from fragmentary specimens.) 



Dikelocephalus minnesotensis Owen, Hall, 1867, Trans. Albany Inst., Vol. 

 5, p. 117, pi. 4, figs. 5-10; pi. 5, figs. 10-12; pi. 6, figs. I, 3, 4. (Reprint 

 of paper of 1863.) 



Dikellocephalus minnesotensis Owen, Whitfield, 18S2, Geol. Wisconsin, 

 1873-79, Vol. 4, p. 187, pi. 3, fig. I. (Describes species and illustrates a 

 pygidium.) 



Dicelloceph'alus minnesotensis Owen, W^alcott, 1886, Bull. U. S. Geol. Sur- 

 vey, No. 30, p. 35, par. 66. (Notes occurrence of species in Highland 

 Range, Nevada.) 



Dicellocephahis minnesotensis Owen, Lesley. i88q, Geol. Survey Pa.. Rept. 

 P. 4, Dictionary of Fossils, Vol. i, p. 198, fig. i. (Reproduces figures 

 from Owen.) 



Dicellocephalus minnesotensis Owen, Miller, 1889, North American Geol. 

 and Pal., p. 544, text fig. 999. (Restored figure of entire dorsal shield.) 



Dikelocephalus minnesotensis Owen ( ?), Walcott, 1891, Bull. Geol. Survey, 

 No. 81, p. 235. (Notes probable occurrence of species in Texas in giving 

 names of fossils.) 



Dikelocephalus minnesotensis Owen, S.\rdeson, 1896, Bull. ^Minnesota Acad. 

 Nat. Sci., Vol. 4, p. 95. (Mentions occurrence of species at localities in 

 ]\Iinnesota.) 



Dr. James Hall in 1863 published a detailed description of all that 

 was known to him of the species, and practically nothing has been 

 added since. No entire specimens of the dorsal shield are known to 

 me. It is probable that there were 12 segments in the thorax as in 

 Saiikia, but this is uncertain. 



The species is confined to the Mississippi valley as far as now 

 known, with the possible exception of a locality in Lincoln County, 

 Nevada, where fragm.ents associated with Saiikia pepinensis appear to 

 indicate its presence. 



F ormation and locality. — Upper Cambrian : St. Lawrence for- 

 mation ; (85) at Prairie du Sac, Sauk County (Cooper Curtice, 

 1884). and (86) at Van Ness quarry, Gibraltar Blufif, Lodi, Colum- 

 bia County (L. C. Wooster, 1883 ; Cooper Curtice, 1884), both in Wis- 



