185/.] MURCHISON SILURIAN ROCKS OF SCANDINAVIA. 41 



Britain, charged with the Pentamerus oblongus, and forms in both 

 countries a clear horizon. 



The fossils are : Fenestella assimilis, Alveolites (Millepora) repens, 

 Coenites intertextus, Ptilodictya {Eschar a) scalpellum, Haly sites 

 catenularius, Orthis calligramma, O. elegantula, O. testudinaria, 

 O. Pecten, O. zonata, Dalm., O. lamellosa, Strophomena depressa, 

 Leptcena transversalis, Orthis (Spirifer) insularis, 0. biforata (Sp. 

 Lynx, Sp. dentatus, Atrypa crassicostis, Dalm., &c), O. biloba (Sp. 

 sinuatuSyY .Bxxch), Cyrtia trapezoidalis, Trigonotreta compressa, Pen- 

 tamerus (Atrypa) galeatus, Atrypa prunum, A. tumida, Pentamerus 

 Lens, P. Icevis, Atrypa reticularis, A. aspera, Dalm., Euomphalus 

 funatus, E. sculptus, Acroculia Haliotis, Calymene Blumenbachii, 

 Encrinurus punctatus, Ampyx, Acidaspis, and the Trilobites ellipti- 

 frons (Proetus ?) of Esmark, Tril. elegans, Sars, &c. 



The band with Pentamerus oblongus is at once followed by 

 another limestone (No. 10) highly charged with corals and crinoids, 

 and which evidently characterizes the mass of the Wenlock limestone. 

 It is, however, important to remark that, with many corals, the 

 Euomphalus sculptus, E. carinatus, and even the Orthoceras annu- 

 latum and O. Ibex, Sil. Syst., we again meet with the Pentamerus 

 oblongus and P. Icevis of the subjacent band, thus linking together, 

 still better than in England, these beds with the inferior strata, and 

 showing a higher vertical range of the above species of Pentameri 

 than is known in England, where they never rise into the Wenlock 

 formation. The list of fossils includes Ptilodictya lanceolata, P. (Es- 

 chara) scalpellum, and the corals, Cyathophyllum turbinatum, Goldf. 

 Ptychophyllum patellatum, several species of Heliolites, and several 

 forms noticed in the underlying strata, with Sarcinula organum, a 

 species of Lower Silurian age in Britain. The prevailing Encrinite 

 is Actinocrinus moniliformis, Goldf., whilst the Cornulites serpula- 

 rias, Sil. Syst., is accompanied by the following shells, Rhynchonella 

 borealis (Ter. plicatella, Dalm.), Euomphalus carinatus, E. sculptus, 

 and other spiral forms, Orthoceras Ibex, O. annulatum, with the 

 Pentamerus conchidium and the other species above noted. The 

 encrinal schists (11) and Upper Orthoceratite-limestone (12), the 

 Upper Graptolite-marls (13) and the Upper Malmo limestone (14), 

 with the schists and marls of Overland, Opsahl, Noes, Krogsand, &c, 

 represent other members of the Upper Silurian, as far as the lower 

 and middle members of the Ludlow rocks inclusive — the Upper 

 Ludlow rock not being well represented by fossils. 



Whilst the ordinary Wenlock Corals seem to pervade all the last- 

 named rocks, their lower members or the encrinal schists and Or- 

 thoceras-limestone, characterized by large Orthoceratites with cen- 

 trals iphuncles, may be supposed to represent the Lower Ludlow, 

 the more so, as it contains Gomphoceras pyriforme, Sil. Syst. In 

 the overlying shales Graptolites (Ludensis) priodon abounds ; but 

 it is to be noted that this zoophyte is associated with the* Retiolites 

 Geinitzianus, Barr., and Cyathocrinus rugosus, both of Wenlock 

 age in Britain the former even pointing to the very base of the 

 formation. 



