412 Forty- second Report on the State Museum. 



Emil Tietze* urged that the normal or classical Devonian, as denned 

 by Murchison and Sedgwick, had for its base the Linton beds, with a 

 fauna equivalent to that of the Spiriferensandstein or Coblenzian, and 

 that a supposably older fauna could not properly be admitted within 

 the original limits of the Devonian division. KAYSERf replied that 

 the same line of argument would exclude from the typical Silurian 

 all the Bohemian etages above E, and thus leave the F, G and 

 H etages and their equivalents in a position between Silurian 

 and Devonian, but belonging to neither; a conception indeed 

 not widely remote from that entertained by Barrande in regard to 

 his upper etages. Barrois J subsequently refers to the fact that the 

 Looe greywackes of Cornwall, which are older than the Linton beds, 

 contain a fauna § probably older than the Coblenzian and, inferen- 

 tially, equivalent to the Taunusian if not to the Gedinnian. 



Tietze further makes the important point, that, as the determination 

 of the faunal quantivalences may be to a large degree a matter of per- 

 sonal opinion, there is no reason why the Graptolite element of the 

 Hercynian is not as conclusive of Silurian age as the Goniatites are 

 of Devonian. Kayser in reply showed that aside from either of these 

 elements the import of the fauna was preeminently Devonian. 



Prof. Clemens Schxuter || demurred to Kayser's position that the 

 Hercynian was a parallel formation of the Spiriferensandstein (Coblen- 

 zian) or a calcareous facies of its normal arenaceous fauna. 



Barrande^" protested that Kayser's identifications of Bohemian 

 species in the Hercynian were of questionable value, and entered into 

 a protracted analysis of the twenty-two brachiopod species, held by 

 Kayser to be identical or analogous in the Hartz and Bohemia, and 

 came to the surprising conclusion that of all these, but one species was 

 correctly identified and that but few of the suggested analogies were 

 admissible. These views have not, however, received general 

 acceptance with the discutants upon this subject. 



In 1881, Kayser** essentially modified his conception of the age of 

 the Hercynian fauna. The Hauptquarzit overlying the Untere Wieder 

 Schiefer or Hercynian had proved itself a representative in part of 

 the Coblenzian, i. e., later Lower-Devonian, and so intimately united 

 petrographically and faunally with the beds immediately beneath, 



* Jahrbuch d. K. K. geolog. Reichsanst. zu Wien, p. 743, 1878. 

 tZeitschr. d. deutseh. geolog. Gesellsch. Vol. xxxi, p. 54, 1879. 

 tFaune du Calcaire d'Erbray, p. 284, 1889. 



§ The species of this fauna are given by Davidson, Brit. Devon. Brachiopoda, vol. 3, pp. 

 106. 126, 1865. 



II Verhandlung des naturhist. Vereins fiir Bheinl. u. Westfalen. p. 330, 1879. 

 HSysteme Silurien du Centre de la Bohenie, Vol. V, p. 167 et seq. 

 ** Zeitsehrift d. deutseh. geolog. Gesellsch. Vol. XXXI, p. 624. 



