^ PALEOZOIC TIME — UPPER SILURIAN. 667 



Characteristic Species. 



1. Upper Llandovery. — Petraia, species of FavnsUes, Ileliolites, Syringopora, Haly- 

 sites, Omphyma., Palceocyclus, Actinocrinus, Palceechinus, Tentaculites ornatus, Cornu- 

 lites serpularius, Coelospira Scotica, Rhynchonella neglecta, Meristella angustifrons, Stro- 

 phomena arenacea, 8. compressa, Peiitamerus ohlongus, P. caudatus, Slricklandinia lens, 

 S. lyrata, Orthis lata, 0. calligramma, 0. elegantnla, Lyrodesma cuneatum, Pterinea sub- 

 Icevis, Murchisonia angulata, M. articulata, Cyclonema quadristriatiim, Euomphaltis ala- 

 tus, Raphistoma lenticulare, Holopella obsoleta, Gomilaria, Galymene Blumenbachii, 

 Encrinurus piaictatus, Illcenus Thomsoni, Proetus Stokesi, Phacops Stokesi ; also 

 Trinucleus concentricus, Lichas laxatus, Acidaspis, etc. 



2. Wenlock Group. — Petraia bina, Cyathophtjlluni truncatum Linn., Favosites (lOth- 

 landicus, F. Jibrosus, Halysites catenulutits, II. interstinctus, Syringopora bifurcata, Cysti- 

 phyllum Sihirie.nse (Fig. 827), Stenopora fibrosa, Ptilodictya scalpellum, and many other 

 Bryozoans ; Eucahjptocrinus decorus, Actinocrinus simplex, Crotalocrinus rugosus (Fig. 

 828), Marsupiocrinus coelatus, Atrypa reticularis, Orthis elegantula, Bhynchonella Wilsoni, 

 P. nucula, Pentamerus galeatus, Leptcena rhomboidalis, Spirifer elevatus, 8. sitlcatns, 

 Nucleospira pisum, Obolus Davidsoni, Turrilepas, Modiolopsis complanata, Gonoeardium 

 CBquicostatum, Pterinea retroflexa, Grammysia cingulata (Fig. 830), Orthoceras, Lituites, 

 Actinoceras, Tentaculites ornatus, Acidaspis coronata, A. hamata, Galymene tuberculosa, 

 Homalonotus dclphinocephalus, Lichas Anglicus, Phacops caudata, Encrinurus variolaris. 



3. Lower Ludlow. — Palceasterina primoiva, Protaster 8edgwickii, P. hirudo, Om- 

 phyma turbinata, Bhynchonella Wilsoni, B. navicula, Gyrtia exporrecta, Spirifer crispus, 

 Strophonella euglypha, Atrypa reticularis, Lingula lata, Pentamerus galeatus, Orthonota 

 affinis, Loxonema sinuosum, Orthoceras Ludense, 0. annulatum, Phragmoceras, Lituites 

 giganteus, Galymene Blumenbachii, Phacops caudata, P. longicarulata, Proetus latifrons, 

 Acidaspis Brightii, Lichas Anglicus, Homalonotus delphinocephalus, Gyphaspis megalops, 

 Memiaspis sperata. 



4. Aymestry Limestone. — Tentaculites ornatus, Gyathophyllum truncatum, Penta- 

 merus Knightii (Fig. 829), Atrypa reticidaris, Bhynchonella Wilsoni, B. navicula, B. 

 Stricklandi, Lingula Lewisii, L. lata, Strophonella euglypha, Meristella ( WhitfieJdella) 

 didyma, Ghonetes striatellus, Bellerophon dilatatus, B. trilobatus, Lituites giganteus, 

 Orthoceras ti'nuiannulatum, Pterinea Sowerbyi, P. Mans, Galymene Blumenbachii, 

 Homalonotus delphinocephalus, Phacops caudata. 



5. Upper Ludlow. — Lingula minima, L. lata, Orhiculoidea rugata, Ati-ypa reticularis, 

 Bhynchonella Wilsoni, Orthis elegantula var. orbicularis, 0. lunata, Stropheodonta filosa, 

 Strophonella euglypha, Ghonetes striatellus, G. latus, Orthonota angulifera, Platyschisma 

 helicites, Holopella ohsoleta, H. gregaria, H. conica, Cyclonema corallii, ILirchisonia 

 corallii, Bellerophon carinatus, Orthoceras bullatum, Homalonotus Knightii, Encrinurus 

 punctatus, Phacops Downingii, Galymene Blumenbachii, Geratiocaris, Dictyocaris, 

 Entomis, Beyrichia, Leperditia, Eurypterus, Pterygotus bilobus (Fig. 831), Slimania, 

 Stylonurus. 



Fishes from the Lower Ludlow include only Scaphaspis (Pteraspis) Ludensis ; from 

 the Upper, mostly from the bone-bed, Gephalaspis ornata, G. Murchisoni, Plectrodus 

 mirabilis, P. pleiopristis, Pteraspis Banksii, P. truncata, Scaphodus Ludensis, Thelodus 

 parvidens, Thysetes verrucosus, and others. Tliere are, also, in the same rocks Coprolites 

 from some of these Fishes, containing fragments of the shells of the Mollusks and Cri- 

 noids on which they fed. Remains of Fishes have also been found in the upper part of 

 the Upper Silurian of Russia and Bohemia. Ctenacanthus Bohemicus Barr, abundant in 

 Stage G. 



The Hercynian fossils of the Hartz and Erbray have closer analogy with those of the 

 Lower Helderberg than with those of tlie Upper Helderberg, but they also have close 



