Report of the State Geologist. 



413 



that the author was disposed to regard the latter no longer as of very 

 early Lower-Devonian age, but possibly equivalent to one of the lower 

 members of the Rhenish Coblenzian, but not so old as the Taunusian 

 or Gedinnian. 



In 1884,* however, in discussing the question of the limit between 

 Silurian and Devonian in Bohemia, Thuringia and elsewhere, without 

 referring directly to the quantivalence of the Hartz Hercynian, he uses 

 the term Hercynian throughout as equivalent to basal Devonian, and 

 we are left to infer that he quietly abandons his view of 1880, return- 

 ing to his original conception of the age of this fauna. In this place, 

 also, reasons are adduced for drawing the dividing line between Silurian 

 and Devonian in Bohemia, not between E and F, but through the etage 

 F between the zones F x and F 3 . This is proposed on the ground of the 

 absence of Devonian piscine types in beds older than F 2 ; the first 

 appearance of Dalmanites (Hausmannia) and Bronteus (Thysanopeltis), of 

 Goniatites, Gyroceras, Stringocephalus, etc., in this zone. 



This subdivision of F was opposed by Dr. Ottomar Novak, Curator 

 of the Barrande Collection in Prague, in 1886, f who demonstrated 

 that the two zones were not consecutive, but most probably continuous 

 and different facies of the same fauna. Novak followed Kayser's 

 original conception of the equivalence of the F, G, H fauna with the 

 Hercynian, and adopted this term for this Bohemian fauna in its 

 entirety .J 



While Kayser, Novak and others still remained disposed to regard 

 the Hercynian of the Hartz as a strictly lower (lowest ?) Devonian 

 deep sea fauna, parallel to the arenaceous fauna in the normal 

 Khenish Lower-Devonian (Coblenzian) and equivalent to the Bohemian 

 faunas from F (F 2 ?) to H, taken in their entirety, the study of the 

 Bohemian faunas with special relations to their equivalence with 

 those of the Rhenish and Westphalian Devonian, educed essential 

 modifications of this view. 



The matter was presented in a new light by Dr. Fritz Fkech, at a 

 meeting of the German Geological Society, December, 1886. § 



* Kayser: Ucber <Ue Gronz© zwischen Silur and Devon (Horeyn) in Bchm-n. Thai in- 

 gen und einigon audeten gegendon; Neues Jahrh. fur Mineral, etc., 1881, Vol. II. p. 81. 



t Zur Kenntniss d. Fauna d. Etage If— f, etc. ; Sitzungsber. d. k. bohm. Gesellsch. d. 

 Wissensch, 1886. 



tWe have purposely avoided r^forence to the phase of the Hercynian discussion, involv- 

 ing the faunas at Bicken. the Greifenstein, Bieber and elsewhere in Westphalia. The 

 encounters between Kayser and Maurer in this direction have been vigorous, but the 

 main issues of the question Appear to be less involved here than in the other fields 

 indicated. See. for example. Maurer; Die Faunader Kalkevon Waldgirmes : Abhandl d. 

 Grossherzog. Hess, geolog. Landesanst zu Darmstadt, Vol. I, Heft 2. 1885, p. 309, and 

 Kayser's review of the same in the Neues Jahrbuch fur Mineral. 1880, Vol. 2, p. 100. 



§ Zeitschr. d. deutsch. geolog. Gesellsch. Vol. 38, p. 917, 1886. 



