RELATIONS OF KONIEPRUSSIAN AND LOWER HELDERBERG 265 



Bohemia, etage F 2 . 

 Retzia haidingeri B. 



A try pa eurydice B. 



Retzia melonica B. (PI. 141). 



Dalmanites hausmanni Brongniart. G. 



Acidaspis monstrosa B. G v 



Phacops breviceps F 2 . 



Fenestella and Hemitrypa in abundant 



development in etage F. 

 Actinostroma, Stromatopora, and Clath- 



rodictyon in numerous examples in F. 



Lower Helderberg. 



Rhynch ospira, form osa Hall. 

 Rhynchosplra glotwsa Hall. 

 Rensselxria mutabilis Hall. 

 Probably another Rensselreria of Lower 



Helderberg development. 

 D. (Odontoclieile) micrurus (Green). 

 Acidaspis tuberculata (Conrad). 

 Phacops logani Hall. 

 An abundant development of these 



forms in the Lower Helderberg. 

 Syringostroma and Clathrodictyon in 



the Lower Pentamerus limestone. 



The foregoing table of equivalents leads the writer to regard the 

 Konieprussian and the Lower Helderberg as closely related, as well as 

 the oldest well described Lower Devonic brachiopod faunas. The great 

 diversity of the fenestelloids in etage F is in harmony with a similar 

 development in the Delthyris shale of the Lower Helderberg. The 

 stromatoporoids are also in harmony with this view. The trilobites do 

 not oppose this correlation, but two characteristic species of the Lower 

 Helderberg — Dalmanites micrurus and Acidaspis tuberculata — find their 

 equivalents in the next higher zone, or etage G. Barrande does not 

 figure the gastropods and pelecypods of Bohemia, and the writer can 

 therefore make no comparisons. The Goniatites said to be of etage F 2 , 

 described by Barrande, are now known to belong in a zone the equiva- 

 lent of G (see Freeh's table on page 263), and therefore do not affect the 

 Lower Helderberg fauna. Even if they occurred in the Konieprussian 

 fauna under review, the fact should be borne in mind that not a single 

 Goniatite is known in America prior to the Corniferous, and that there 

 is but a meager representation in any American Middle Devonic horizon. 

 The weight of this argument, therefore, loses its force in point of correla- 

 tion. On the other hand, of the 6 species of Goniatites said by Bar- 

 rande to be from etage F 2 , but 2 are restricted to that horizon — G. solus 

 and Agoniatitesfidelis — while the other 4 also occur in G 3 — G. plebius B. 

 = Anarcestes latiseptatus (Bey rich), Agoniatites verna, Anarcestes crispus, 

 and Agoniatites tabidoides — and 2 of these persist into H x — Anarcestes 

 latiseptatus (Beyrich) and Agoniatites verna. These species thus show 

 that they have no particular stratigraphic value beyond the fact already 

 mentioned, which seems strong proof for a Devonic facies. The writer 

 therefore concludes that the Konieprussian (F 2 ) and the Lower Helder- 

 berg are the equivalents of each other and represent the best known 

 lowest Lower Devonic faunas. 



XXXIX— Bui.t,. Geol. Soc. Am., Vot,. 11, 1899 



