PALEOZOIC TIME — UPPER SILURIAN. 569 



Coelospira Scotica, Clinton, Great Britain (May Hill). 



Bhynchonella Udentata, Niagara, Great Britain (Wenlock). 



Bhynchotreta cuneata, Niagara, Great Britain (Wenlock), Gothland. 



Bhynclionella Wilsoni, Niagara, Great Britain (Wenlock). 



Bhynchonella Stricklandi. 



Pentamerus galeatus, HeMerherg, Great Britain (Wenlock, Ludlow), Eifel. 



Pentamerus brevirostris, Niagara, Great Britain (Devonian). 



Pentamerus ohlongus, Clinton, Niagara, Great Britain (Wenlock). 



Pentamerus Icevis, Great Britain (Wenlock). — P. Knightii, Great Britain (Ludlow). 



Anastrophia interplicata. Great Britain. 



Bellerophon bilohatus, Trenton to Clinton, Great Britain (Wenlock). 



Orthoceras annulatum, Clinton, Niagara, Great Britain (Wenlock, Ludlow). 



Orthoceras virgatum, Niagara, Great Britain. 



Calymene tuberculosa, Niagara, Great Britain (Bala, Wenlock, Ludlow), Sweden, Norway, 



Bohemia, France. 

 Homalonotus delphinocephalus, Clinton, Niagara, Great Britain (May Hill, Wenlock). 

 Proetus Stokesi, Niagara, Great Britain (Wenlock). 

 Trinucleus concentricus, Trenton, Hudson, Great Britain (May Hill). 

 Tentaculites ornatus. Water-lime, Great Britain (May Hill, Ludlow). 



Arctic American Upper Silurian Species Occurring Elsewhere. 



Stromatopora concentrica, Great Britain, Eifel. 



Halysites catenulatus. Great Britain, Norway, Sweden, Russia, United States. 



Favosites Gothlandicus, Great Britain, Sweden, United States. 



Favosites polymorphus. Great Britain, France, Belgium, Eifel. 



Beceptaculites Neptuni, Great Britain, Belgium, Eifel, United States. 



Orthis elegantula, Great Britain, Gothland, Russia, United States. 



Atrypa reticularis, Great Britain, Gothland, Urals, Altai, United States. 



Pentamerus conchidium, Gothland. 



Encrinurus Icevis (?), Gothland. 



Leperditia Baltica, Gothland. 



The number of Lower Llandovery (top of Lower Silurian) species that are known to 

 pass into the Upper Silurian in Great Britain is 104 in 45 genera, out of a fauna of 204 

 species in 68 genera (Etheridge). 



Devonian Relations of the Loiver Helderberg Fauna. 



This subject has been ably discussed by J. M. Clarke, in the 42d Annual Report of 

 the New York State Museum, 1889, under the title "The Hercynian Question." The 

 terms Hercynian shales and Hercynian fauna were first given by E. Kayser, in a paper 

 on the oldest Devonian formations of the Hartz Mountains, to the second of four for- 

 mations in the region — the " Unterer Wieder Schiefer" of A. Roemer. It contains the 

 oldest fauna of the Hartz, and was pronounced by him the oldest or lowest Devonian, 

 and also the equivalent of Barrande's Upper Silurian divisions, F, G, H. 



Clarke gives the following summary of the history of Hercynian ideas : " A. Roemee, 

 in 1843, regarded the fauna in the Hartz, in its typical development, as Upper Silurian ; 

 but subsequently made the Cephalopod facies and Brachiopod facies thereof represent 

 distinct faunas, the former Devonian, the latter Silurian. Beyrich, in 1867, believed the 

 two faunas of Roemer one, and suggested their equivalence to the Bohemian F, G, H, and 

 their relation to the Devonian. Kayser, in 1878, demonstrated their unity and Devonian 

 character and regarded them as the lowest Devonian, and as representing a calcareous 



