Report of the State Geologist. 



409 



regarded as a richly fossiliferous Lower-Devonian limestone formation, 

 which was related to sparsely fossiliferous Lower-Devonian shales and 

 greywackes, just as is the richly fossiliferous Carboniforous limestone 

 to the sparsely fossiliferous Culm. 



The propositions of Beyrich, though made informally and left to 

 await elaboration for a period of eleven years, embody the germ of 

 the whole discussion of the " Hercynian question," which, for eleven 

 years past, has been the chief concern of pakeozoic geology upon the 

 continent of Europe. 



In 1878 appeared Prof. Emanuel Kayser's now justly famous work 

 on the " Fauna of the oldest Devonian Formations of the Hartz 

 Mountains." * 



This was a most detailed and incisive presentation of Beyrich's 

 proposition, embodying the description of a very considerable fauna 

 from the lenticular limestones of Zorge, Wieda, Magdesprung, Hassel- 

 felde, etc., and affording comparisons with all known faunas present- 

 ing features indicative of equivalence. 



In the region under consideration the nomenclature applied to the 

 formations by A. Roemer, was as follows, beginning with the oldest: 



Tanner Grauwacke Untere Wieder Schiefer Hauptquarzit • 



Obere Wieder Schiefer. The Tanner Grauwacke bearing only (with a 

 possible exception) plant remains, Knorrias, Sagenaria, Lepidodendron, 

 etc., had been referred by Roemer, at certain of its outcrops, to the 

 Culm, and though previously to 1878, it was recognized in Lossen's 

 geological map of the Hartz, as at the base of the palseozoic formations 

 of this region, its characters did not come up for extended considera- 

 tion. The Hauptquarzit was subsequently shown to contain a fauna 

 essentially equivalent to that of the Spiriferensandstein of the Kahle- 

 berg and Schalke in the lower Hartz. The Untere Wieder Schiefer 

 constitute the beds bearing the oldest fauna of the Hartz. In their 

 outcrops neither continuity nor consecuity can often be traced, but 

 they were divided by Kayser into : " Shales of the lower zone with 

 the limestone fauna of Magdesprung, Hasselfelde, Zorge, Ilsenburg, etc., 



and with the plant-bearing greywackes of Strassberg, Stolberg, etc. 



"Shales of the upper zone" "Graptolite horizon." This series 



(Untere Wieder Schiefer) was designated "Hercynian shales" and its 

 fauna as a whole, the "Hercynian fauna." 



The characteristic elements of this Hercynian fauna (in which the 

 number of species rose to 200) were as follows: 



Devonian. Brachiopods: Abundant Spirifers (17 species), among 



♦Die Fauna der itltesten Devon-Ablasrerungen des Harzes: Abhandl. zur geolog. 

 Special Karte Preuss. u. den Thiir. Staat, Bnd II. Heft 4, 1878. 



52 



