TV. A. E. JJssher — The Culm of Devonshire. 11 



also showed that these typical rocks had their equivalents along the 

 southern margin of the great Culm Measure Synclinal. 



Phillips gives the following grouping of the Culm Measures in the 

 south part of their range. 



Upper or Grit Group of Central Devon. 



Upper Shale Group — A mass chiefly of dark shales, carbonaceous grits and shales, 

 the lowest part being the Coddon Hill chert series. 



Middle or Calcareous Group — Limestone, mostly black, irregularly bedded, asso- 

 ciated with shales, often resting on trap rock and fossiliferous. 



Lower Shale Group — Black argillaceous plate, or very laminar shale, not subject 

 to slaty cleavage, and scarcely fossiliferous. 



" Following the line of the carbonaceous group of North Devon to 

 the east," says Phillips, p. 194, " it is lost under the superimposed 

 red marls and sandstones ; these range nearly north and south across 

 the general strike of the carbonaceous group and conceal it . . . On the 

 west the carbonaceous group occupies the coast from Fremington nearly 

 to Tintagel, and on the south it follows a line much bent by the 

 effect of the protruding granitic masses, especially of Dartmoor. In 

 the centre of this great district no limestone occurs, and there are no 

 other fossils than obscure marks of plants or mere carbonaceous 

 stains ; but on the southern border the limestone bands reappear 

 almost exactly as on the northern side with similar mineral characters 

 and accompaniments, and similar or identical organic remains ; for 

 example, at Trescott near Launceston, Lew Trenchard, Bridestow, 

 and Okehampton." 



Beds of Anthracite occur in the Culm Measures of North Devon in 

 the neighbourhood of Chittlehampton, Tawstock, Abbotsham, and 

 Alverdiscot ; they are alluded to by Polwhele,^ by Vancouver,^ by 

 Lysons,^ by Sedgwick and Murchison,* and De la Beche ;'* the latter 

 says: "Anthracite or Culm occurs in a few beds of very variable 

 thickness between Greenacliff on the coast west from Bideford and 

 Hawkridge Wood near Chittlehampton." 



" Sufficient Anthracite was at one time raised near Greenacliff, in 

 Barnstaple Bay, to burn with the limestone brought there from South 

 Wales." 



Mr. T. M. Hall (Trans. Dev. Assoc, for 1875), in a paper entitled 

 " Notes on the Anthracite Beds of North Devon," says : " The widest 

 culmiferous band is neai'ly 18 feet in width, but several smaller 

 strings of the same material traverse the slates and shales. 



" At Bideford, a few yards north of the Eailway Station, may be 

 seen the black shales forming the outcrop of the veins which, until a 

 very recent period, were worked to a considerable extent. . . . About 

 a mile east of this spot the present works, consisting of a shaft and 

 level adit, are still carried on for the purpose of obtaining the softer 

 varieties of Anthracite, which when ground to powder are sold as a 

 pigment under the name of Bideford Black." 



1 History of Devonshire, p. 56 (1797). 



2 Genei-al View of the Agriculture of the County of Devon, p. 266 (1808). 



3 Magna Britannia Devon (1822), p. 266. 



* On the Physical Structure of Devonshire (1840). 

 5 Eeport on Geol. Corn. Devon, etc. (1839), p. 513. 



