198 CARBONIFEROUS. 



also been met with. The upper beds of the Culm-measures, 

 according to Mr. Ussher, include the fine-grained even-bedded 

 grits of Eggesford (Eggesford grits) south of Chumleigh. They 

 contain subordinate beds of shales and slates, and occur over the 

 area between Hatherleigh and Torrington, at Iddesleigh, etc. The 

 middle beds of Culm-measures consist of sandstones, grits, and 

 shales, with beds of culm, and outcrop to the north and south of 

 the Eggesford grits, which overlie them. They comprise rather 

 coarse grits and shales, with culm near the base, and are developed 

 at Hartland Point, at Bideford, Morchard Bishop south-east of 

 Chumleigh, and Umberleigh between Chumleigh and Barnstaple. 



The Coddon Hill Beds, of Coddon Hill, south-east of Barnstaple 

 (described by Phillips), consist of pale grey, or black chert, in 

 thin striped beds like some of the bedded chert of Leyburn, in 

 Wensleydale. Black grits, with jasper rock and lydian stone, and 

 shales of variable thickness, go to make up this series, the total 

 thickness of which was estimated at from 1500 to 2000 feet by 

 the Rev. D. Williams.^ Oiihocems, Goniatites, and Posidonomya 

 occur in the shales. 



The lowest beds comprise a series of black shales with thin grits 

 and impersistent bands of dark or black limestone (Culm-limestone), 

 containing similar fossils, and known as the Posidotiomya {Posidonia) 

 limestone. This limestone extends from Bampton to Fremington, 

 near Barnstaple, and has been worked at Instow, Swimbridge, and 

 Venn near Barnstaple, and near South Molton, frequently ex- 

 hibiting remarkable folds and contortions. 



The limestones are also exhibited at Westleigh and Canonleigh, 

 near Holcombe Rogus, and Hockworthy, between Wellington 

 and Tiverton, where the beds also are much disturbed. From 

 the last-named localities the Rev. W. Downes has obtained Cho7ietcs 

 Lagiiessiana (C Hardre7isis ?), Orthis MichcUni, and Spin/era, also 

 Posidonomya Becheri and Goniatites? 



No limestones appear in the centre of the Culm-measure district, 

 but they reappear in South Devon at Trescott, near Launceston, 

 Lifton, Lew Trenchard, Bridestow, Oakhampton, South Tawton, 

 and Drewsteignton. Remains of Coclacanthus have been met with 

 at Instow. 



Certain black shales at or near the base of the Culm-measures in 

 South Devon have hitherto been regarded as yielding few fossils; 

 but in 1884 IMr. J. E. Lee obtained a number of interesting speci- 

 mens, including Trilobites, from shales that overlie the Devonian 

 Limestones at Waddon Barton, near Chudleigh. These include 

 four species of PhiUipsia (described by Dr. Henry Woodward), 

 together with Goniatites sphccricus, Orthoccras striolatiun, Posidonomya 

 Bcchcri, Avicula lepida, Chonetes deflexa, Spirifera Urii, etc.^ These 



' Proc. G. S. iii. 116 ; De la Beclie, Report on the Geology of Cornwall, etc. p. 

 lOl and P. G. S. ii. 106 ; Phillips, Paleozoic Fossils of Cornwall, etc. pp. 189-195 ; 

 Sedgwick and Murchison, T. G. S. (2), v. 670 ; H. B. HoU, Q. J. xxiv. 400. 



- Trans. Devon Assoc. 1878 and 1879. 



3 G. Mag. 1884, p. 538. 



