626 



HISTORICAL GEOLOGY. 



containing many Crinoids and Brachiopods : Fentremites ovalis, Athyris concentrtca, 

 Spirifer decussatus, S. Urii, Orthis plicata, 0. parallela, 0. interlineata, Productus 

 prcelongiis, Streptorhynchus crenistria ; with several species of Clymeiiia, Goniatites, 

 Orthoceras ; also Phacops latifrotis, etc. 



Among the Devonian plants of Ireland, in beds that contain also remains of Coccos- 

 teus and Glyptolepis, there are Cyclopteris Hibernica Forbes, Spkenopteris Hookeri Baily, 

 8. Humphriesiana, Calamites radiatus Br., Lepidodendron Veltheimanum Sternb., Knor- 

 ria acicularis Gopp., Cyclostigma minutum Haughton, C. KiUorkense Haughton, and 

 other species. The whole number known of species of Fishes from the Lower Devonian 

 of Great Britain, as stated by Etheridge in 1885, is 88, 4 species of Onchus being ex- 

 cluded ; in the Middle Devonian, 2 ; in the Upper, 28. The only genera common to the 

 Lower and Upper are Pterichthys, Asterolepis, Holoptychius and Platygnathiis. Of the 577 

 species in the fauna, 50 pass up into the Carboniferous. 



In the Ardennes, on the borders of France and Belgium, there is the west border of a 

 broad Devonian area which crosses the Rhine north of jNIayence with bold features along the 

 river, and extends to Nassau and Westphalia. The Lower, Middle, and Upper divisions are 

 named(l) the Phenan,(2) the PJifeUan, and (3) the Famennian. In the region of the 

 Ardennes the Lower consists, according to Gosselet, of (1) the (Tec?iHH?'a)?,about2500' thick, 

 containing Homalonotus, Tentaculites, Spiirifer Dumonti ; (2) the Taumisian, about 1800' 

 thick, with Fleurudictyon, Leptcena JInrchisoni, L. laticosta ; (3) the Coblenzian, about 

 8000' thick, with Strophomena depressa, Grammysia Hamiltonensis ( = bisidcata) ; and at 

 top, Spirifer cidtrijngatits, Calceola sandalina (the latter, perhaps, Eifelian). The Middle 

 or Eifelian, over 3000' thick, includes the Calceola slates, and above these the Givet lime- 



986-987. 

 986. 986 a. 987. 



Cephalopods. — Figr. 986, Glymenia Sedgwneki ; 986 a, dorsal view of septa ; 9ST, Goniatites retrorsus. 



9S6, D'Orbigny ; 987, Vogt. 



Fig. 



Stone (Givetian) or Stringocephalus beds ; the former containing Phacops, Bronteus, Orthis 

 striatula, Productus subaculeatus, Fentamerus galeatus ; the latter, Stringocephalus 

 Burtini, HelioUtes porosus, etc. The tapper or Famennian, over 2500', consisting of the 

 Frasnian shales and limestone below, and the Famennian shales and Sandstones of 

 Condros above, with Atrypa reticularis, Orthis striatula, Spirifer Verneuili (S. disjiinctus) , 

 Clymenia, Archceopteris Hibernica, Sphenopteris flaccida. The Devonian outcrops also to 

 the northwest in the Boulonnais, in Brittany and the Vosges, and to the eastward, in the 

 Harz and Thurinsia. 



