NO. 13 DIKELOCEPHALUS AND OTHER GENERA 359 



Stones of the Franconia formation upward through the St. Lawrence 

 formation into the base of the Jordan sandstone of Wisconsin and 

 Minnesota. 



In Missouri Calinnella ozarkcnsis (pi. 70, figs. 1-6) is associated 

 with a large and varied fauna in which the Gastropoda and Cephalo- 

 poda are strongly developed. It thus appears to belong in a later 

 fauna than the Jordan. Calvinella tenuisculpta from the lower 

 Pogonip limestone of Nevada is also from about the same horizon as 

 C. osarkensis. With it are associated the following : 



(Locality 201a) "Lower Ordovician " (Ozarkian or Canadian) : 

 Pogonip limestone, east slope of the ridge east of Hamburg Ridge, 

 Eureka district, Eureka County, Nevada (C. D. Walcott, 1882) : 



Obolus {Westonia) iphis Walcott Apatokephalus Unalis (Walcott) 



Lingulella pogonipcnsis (Walcott) Conokephalina incxpectans (Wal- 

 Acrothele sp. cott) 



Acrotreta idahoensis Meek Agraulos f annectans (Walcott) 



Schizamhon typicalis Walcott Aitomocarclla owcni Meek and Hay- 

 Eoorthis hambmgensis Walcott den 



Syntrophia nundina Walcott Amphion ?f sp. undt. 



Tellinomya ? hamhurgcnsis Walcott Chuangia mccoyi Walcott 



Agnostics prolongns Hall and Whit- lUccnurus ? eurekensis Walcott 



field Asophns ? carihoucnsis Walcott 



Traces of Dikelocephahis are found in the southern Mississippi 

 area in Oklahoma and Texas in the Upper Cambrian. The associated 

 fauna in Texas includes Saiikia fallax and in addition the following: 



(Locality 70a) (below the fauna of locality 70) Upper Cambrian: 

 Wilberns formation ; Baldy Mountain, near Morgan's Creek, 8 miles 

 (12.8 km.) northwest of Burnet, Burnet County, Texas (C. D. Wal- 

 cott, 1884). 



BillingscUa coloradoensis (Shumard) Dikelocephahis texanus Walcott 

 Nileus ? dia (Walcott) Saukia fallax Walcott 



Lonchocephaliis ivisconsincnsis Owen Osceolia osccola (Hall) 



Dikelocephahis.- — Of the seven species referred to the genus Dikelo- 

 cephahis as restricted in this paper the stratigraphic position of all is 

 knowm with the exception of D. ? dalyi n. sp. The type species of the 

 genus, D. minnesotensis Owen, is recorded in literature as occurring 

 at many localities, but I have inserted in this paper only those localities 

 represented in the United States National Museum collections. It 

 will be necessary to have more systematic and careful stratigraphic 

 work and collecting done before any more accurate statement can 

 be made. 



