OLENELLUS AND OTHER GENERA OF MESONACID.E 287 



Holtiiia MoBERG (in part). 1899, Geol. Foren. i Stockholm Forhandl., Bd. 



21, Hafte 4, p. 318. (Briefly characterizes genus. As characterized the 



genus inckides species now referred to Callavia.) 

 Hohnia IMatthew, 1899, American Geologist, Vol. 24, p. 59. (Reviews 



Moberg's paper [1899I and notes two types placed under Hohnia.) 

 Hohnia Weller, 1900, Ann. Rept. Geol. Survey New Jersey for 1899. pp. 



50-51. (Discussed.) 

 Hohnia Pompeckj, 1901, Zeitschr. Deutschen geol. Gesellsch., Vol. 53, 



Heft 2, pp. 14-17. (Olenopsis is compared with Holniia and other 



genera of the Mesonacidse.) 

 Hohnia Lindstrom, 1901, Kongl. Svcnska Vet.-Akad. Handlingar, Bd. 34, 



No. 8, p. 24. (Considers Hohnia an eyeless trilobite, with beginning 



suture.) 



Hohnia is characterized by intergenal spines iti the adult, a uniform 

 series of thoracic segments and 'a small more or less transverse py- 

 gidium with only traces of transverse furrows indicating segments 

 in the median lobe. 



Genotype. — Paradoxides kjerulfi Linnarsson, 1871. 



The onl}- American species of the genus I recognize is Hohnia 

 rozi'ci Walcott. 



Strafigraphic range. — Lower Cambrian. In Scandinavia the 

 Hohnia kjeriilil zone is just beneath the Paradoxides bearing strata. 

 In Sweden it is overlain by the Paradoxides tessini zone [Holm, 1887, 

 p. 514], and in Norway by the P. oJandiciis zone [Idem, p. 514]. 



Hohnia rozvei Walcott occurs low down in the Lower Cambrian 

 in association with Nevadia iveeksi Walcott. 



Geographic distribution. — Scandinavia in Europe ; southwestern 

 Nevada in the L^nited States. 



Obserz'ations. — The generic relations and position of Holniia in 

 the Mesonacida^ are considered in observations on the ^Iesonacid?e 

 [p. 247]. 



From the occurrence of Hohnia kjerulfi just beneath the. Paradox- 

 ides zone in Scandinavia with associated genera closely allied 

 to those in the Paradoxides fauna it is probable that the genus 

 occurs in the upper portion of the Lower Cambrian in western 

 Europe. In the southwestern L^nited States, in Nevada, Hohnia 

 roz'L'ei is found over 4,500 feet below the zone of Olcnelhis gilberti. 

 I strongly suspect that there is a lost interval in the Scandinavian 

 section between the zone of Hohnia kjerulfi and Paradoxides olandi- 

 cus that may represent a portion of the section between Olenelhis 

 and Hohnia in Nevada. That Oh-)ielhts is not found in Scandinavia 

 also strengthens this view, as Olenelhis is very characteristic of the 

 higher beds of the Lower Cambrian in both eastern and western 

 North America. 



