68 Perner & Kodym — Zonal Division and 



Bronteus umoellifer; others are rare and mostly frag- 

 mentary. Their geological distribntion in other Silnrian 

 and Devonian beds of Bohemia is very interesting and 

 important, as may be seen from the following table : 



E 2 F x F 2 G-l G 2 



Acidaspis vesiculosa Beyr x x 



Bronteus umoellifer Beyr x 



Crotalocephalus gioous (Beyr.) x x x 



C rot aloe ephalus sternbergi (Boeck) x x x x 



Cyphaspis hydrocephala A. Roem x x x 



Harpes mieroporus Novak x 



Harpes venulosus Corda x x 



Phacops miser Barr x 



Proetus heteroclytus Barr x 



Proetus lepidus Barr x 



Proetus micropygus Corda x x 



We see that besides five species confined to ¥ l9 there are 

 five which pass into the Lower Devonian (F 2 ) ; they are 

 very rare in F l7 bnt common in the reef limestone of F 2 

 (Koneprusy). It may be that the uppermost trilobite- 

 bearing beds of this horizon belong already to the Lower 

 Devonian. This possibility is also indicated by other cir- 

 cumstances, such as the absence of the reef limestones of 

 F 2 above the true Fj beds, which are in turn succeeded 

 directly in many places by the upper division of F 2 beds. 

 It would thus seem that these uppermost trilobite-bearing 

 Fi beds are merely "normal' ' shaly deposits, contem- 

 poraneous with the Lower Devonian white reef limestones 

 of F 2 , a theory which might also explain the other great 

 differences between upper F x and F 2 . 2 



!2 



22 Without dwelling longer on the Hercynian question in Bohemia, I will 

 restrict myself here to the following remarks: (1) 0. Novak (Sitz. d. kgl. 

 bohm. Ges. d. Wissensch., 1886) endeavored to prove that all of F t is equiva- 

 lent to F 2 and therefore of Devonian age, a view which can no longer be sus- 

 tained; (2) the Fi fauna exhibits a Silurian aspect (many species common 

 to E 2 , frequent graptolites, absence of goniatites, see the f aunal list given by 

 Novak and additions to it by zelizko (Verh. geol. Beichsanst., Wien., 9-10, 

 1898) ) ; (3) the different opinions on F x and F 2 contained in the papers of 

 Kayser, Holzapf el, Katzer, Freeh, Seeman, etc., are to be corrected in accord- 

 ance with the researches of Kodym (Bohem. Acad. Sci., 1918), which prove 

 that F 2 a (white reef limestone of Koneprusy) is a distinct lower horizon, 

 succeeded by F 2J S (red marbles of Slivenec), the latter being identical with. 

 Kayser 's and Holzapf el 's " Menaner-Facies ' ' of F, (crinoidal limestones). 



The surprising results of Barrois and Pruvost on the passage beds and 

 boundary between Silurian and Devonian in the Calais coal basin, accepted 2 by 

 Stamp for Shropshire and southern Wales, beeame known to me too late to 

 be taken into consideration in discussing and correlating the F x beds in the 

 present paper. 



