m the Culm-shales of Devonshire. 537 



1876. — Mr. Horace B. Woodward, in his ' Geology of England 

 and Wales/ pp. 106 — 111, gives a concise account of the Devon- 

 shire Culm-Measures. " Looked at it in a large way, they consist 

 of a series of shales, grits, chert-beds, with beds of limestone here 

 and there." "Some authorities have placed them, generally, on the 

 horizon of the Millstone-Grit, but there seems reason to include with 

 them representatives of at least a portion of the true Coal- Measures, 

 and possibly also of the Carboniferous Limestone." 



L — The Nokth-Devon series of Carboniferous deposits about 

 Barnstaple and Bampton is thus given by Prof. Phillips (p. 189) :' 



(a) " Upper part anthracitiferous, and containing ironstone, and by 

 these characters agreeing with the Coal-deposits of Pembrokeshire. 

 This is in general a Gritstone series, with plants of the Coal-formation. 



(6) " Coddon-Hill cherts, black-grits, jasper-rock, lydian-stones, 

 and shales of considerable, but variable, thickness ; 1500 to 2000 

 feet (according to the Kev, D. Williams). 



(c) " Limestone and black shale with Posidonomya, Goniatites, etc. 

 — Posidonomya (Posidonia) limestone of Swimbridge and Venn. 



(d) " Black shale group." 



II. — The South-Devon strata about Trescott and Lew Trenchard 

 have been thus divided (op. cit. p. 194) : 



(a) " Gritstone group of Central Devon. 



(h) "Upper shale group — dark shales, carbonaceous grits and 

 shales (equal to the Coddon-Hill series). 



(c) " Calcareous group — limestone of dark colour, and irregular 

 bedding, with shales (Posidonomya). 



(d) "Lower shale group, with few fossils (no slaty cleavage)." 



1879.— In this year the Eev. W. Downes, M.A., F.G.S., com- 

 municated a paper " On the Limestones of Westleigh and Holcombe 

 Eogus," to the Trans. Devonshire Association, vol. ix. pp 433-441. 



1882. — Dr. A. Geikie, F.R.S. (the present Director-General of the 

 Geological Survey of Great Britain), writes in his "Text-Book of 

 Geology " (p. 748) as follows : 



"In Moravia, Silesia, Poland, and Eussia, the Carboniferous Lime- 

 stone reappears as the base of the Carboniferous system, but not in 

 the massive calcareous development which it presents in Belgium 

 and England. One of its most characteristic phases is that to which 

 the name ' Culm ' (applied originally to the inferior slaty coal of 

 Devonshire) has been given, when it becomes a series of shales, 

 sandstones, greywackes, and conglomerates, in which the abundant 

 fauna of the limestone is reduced to a few molluscs (Productns 

 antiquus, P. latissimus, P. semireticulatus, Posidonomya Beclieri, 

 Goniatites sphoericus, Orthoceras striatidum,'^ etc.). The Posidonomya 

 particularly characterizes certain dark shales known as ' Posido- 



1 '< Figures and Descriptions of the Palaeozoic Fossils of Cornwall, Devon, and 

 West Somerset," by Prof. John Phillips, F.R.S., 1841, 8vo. 



'•^ 0. strioiatum, Sandb. The above-mentioned shells, which are all marine, occur 

 in the Calciferous Sandstone around Edinburgh and in Fifeshire (see paper by Mr. 

 R. Etheridge, jim., "On the Invertebrate Fauna of the Lower Carboniferous or 

 Calciferous Sandstone of Edinburgh," etc., Quart. Journ. Geol. Soc. 1878, vol. xxxiv. 

 pp. 1-26, plates i. and ii. 



