PALEOZOIC TIME — DEVONIAN. 



625 



through. Two species of Myriapods have been described from the lower Old 

 Eed sandstone of Forfarshire, Scotland, Kampecaris Forfarensis Page, and 

 Archidesmus MacNicoU Peach. 



The Pishes of the Old Eed sandstone have come mostly from bituminous 

 flags in northern Scotland and North Wales, and include species of the 

 Placoderm genera Cejjhcdasjns (Fig. 980), Pteraspis, Cyathaspis, Auchenaspis, 

 Holaspis; Asterolepis, Pterichthys (Figs. 982, 983), Bothriolepis, Coccosteus 

 (Fig. 981); also the Dipnoan genera, Dipterus, Phaneropleuron ; and the true 

 Ganoids, Holoptychius, Glyptolepis, Dendrodus, Cheir acanthus. The Cephal- 

 aspids are absent from the Uj^per Devonian of Scotland. 



984-985. 



985 



984 a. 



Gakoh). — Fig. 984, Holoptychius (xf) ; 984 a, a scale. Dipnoan. — 985, Dipterus macrolepidotus (x|) ; 985 a, 



a scale. 



The Devon beds have an estimated thickness of 10,000' to 12,000'. They afford a large 

 variety of Corals, Brachiopods, and other species, a number of them related to those of the 

 American Devonian. i The Lower, Middle, and Upper divisions are : (1) the Lower or 

 Ltnton group of sandy slates and grits, affording Actinocrimts tenuistriatus, Favosites 

 cervicornis, Orthis arcuata, 0. granulosa., Spirifer canaliferus, S. hystericus, S. Icevicostatus, 

 Streptorhyrichus umhracxdum, Chonetes Hardrensis ; (2) the Middle or Ilfeacombe group 

 of slate and grits, witli beds of limestone, containing several species of Crinoids ; many 

 Corals, including Heliophyllum Halli, Cyathophylhim cmspitosum, species of Favosites, 

 Acervidaria, etc.; Stromatopora of several species ; Atrypa reticularis, A. Icevis, A.aspera, 

 Bhynchonella cuboides, Merista pleheia, Orthis striatida, Spirifer curvatus, S. disjunctus, 

 Stringocephalus Burtini, Streptorhynchus crenistria, Strophomena rhomhoidalis, Platy- 

 ceras vetustum, species of Euomphalus, Loxonema, Murchisonia ; Goniatites, Orthoceras, 

 Cyrtoceras ; Tentacidites scalaris; Phacops latifrons, P. granidata, and also species of 

 Bronteus, Harpes and Ceraurus ; (3) Upper, including Pickwell Down and Pilton beds, 



1 In the following lists of foreign species, the new generic names of Brachiopods, recently 

 introduced by Hall and Clarke in their revision of the subject, are not inserted, as they are not 

 yet in use in any foreiscn work on geology or paleontology. 

 Dana's manual — 40 



