DEVONIAN AND OLD RED SANDSTONE SYSTEM 199 



Echiiwderma. Sphserocrinus geometricus, Hexacrinus interscapuUriH, 



Cupressocrinus crassus. 

 Crustacea. Proetus batillus, Bronteua granulatus, B. flabellifer, 



Phacops Schlotheimi, Cypnaspis ocellata. 

 Brachiopoda. Atrypa reticularis, A. desquamata, Stringocephalus 



Burtini, Pentamerus brevirostris, Merixtvlla plebeia, 



Spirifer undatus, S. speciosuR, Uncites gryphus, 



Streptorhynchus umbraculum, Cyrtina heteroclita. 

 Lamellibranchia. Megalodon abbreviatus, Conocardium clathratum, 



Cypricardinia scalaris, Actinopteria placida, Rutotia 



ellipticu. 

 Gastropoda, etc. Loxonema reticulatum, Macrochilina arculatum, 



Murchisonia turbinata, M. coronata, M. bilineata, 



Pleurotomaria delphinuloides, Philozene laevis, P. 



serpens, Porcellia bifida. 

 Cephalopoda. Agoniatites occultus, Anarcestes subnautilinus, Mimo- 



ceras gracile, Hteneceras decheni, M. inolarium, 



Trochoceras obliquatum, Orthoceras laterals, Gyro- 



ceras nodosum. 

 Pisces. Species of Heterosteus, Coccosteus, and Homosteus. 



Fossils of the Upper Devonian 



Aetinozoa. Acervularia Ooldfussi, A., pentagona, Cbonophyllum 



perfoliatum, Phillipsastraea Hennahi. 



Echinoderma. Actinocrinus Porteri. 



Crustacea. Phacops granulatus, P. lati Irons (also in Mid. Dev. ), 



Entomis serrato-striata. 



Brachiopoda. Spirifera Verneuilli, S. Urei, S. distans, Orthis in- 

 terlineata, Strophalosia productoides, Rhyuchonella 

 cuboides, R. laticosta, R. letiensis. 



Lamellibranchia. Ptychopteria damnoniensis, Cucullaea unilatcralis, 

 Ctenodonta (Palaeoneilo) lirata, Myophoria deltoida, 

 Prothyris scalprata, Aviculopecten nexilis, Cardiola 

 retrostriata (Cardium palmatum), Posidonomya 

 venusta. 



Gastropoda. Loxonema anglicum, Pleurotomaria aspera. 



Cephalopoda. Gephyroceras intumescens, Tornoceras simplex, Belo- 

 ceras sagittarium, Clymenia undulata, Clymenia 

 striata, Bactrites gracilis. 



B. BRITISH DEVONIAN ROCKS 



In Britain the only surface exposures of undoubted marine 

 Devonian rocks occur in Devon, Somerset, and Cornwall ; they 

 occupy the northern parts of Devon and Somerset between Morte 

 Bay and the valley of the Tone, as well as the outlying tract of the 

 Quantock Hills, east of that valley. Dipping southward beneath 

 the central Carboniferous area, they reappear in South Devon and 

 North Cornwall (see map, Fig. 64). 



The strike of these rocks is nearly due east and west, and this 

 appears to be maintained in their subterranean extension through 

 the south of England, for rocks with the same Devonian fosails 



