PILTON BEDS. 1 29 



Among the fossils zxo. Phacops latifrons (hence the name Trilobite 

 Slates, used for these beds by the Rev. D. Williams), Cyathocrhms 

 pinnatus, C. variabilis, Euoynphalus serpens, Strophomena analoga, 

 Strophalosia productoides, S. caperata, Streptorhynchiis crenistria, 

 Spirifira disjiincta, Rhy?icho7iella pleurodoji, Cho?ietes Hardrensis, 

 Prodiiclus pnclongus, Avicula damnonicnsis, BeUerophon decjissatiis, 

 Fenestclla antiqua, Pttraia celiica, etc. With the Pilton Beds are 

 included in ascending order, the Croyde Beds (of Croyde Bay), the 

 Braunton Beds (of Braunton, north-west of Barnstaple), the Pilton 

 Beds, and the Barnstaple Beds. 



Besides the above-mentioned localities there are quarries at 

 Goodleigh, and at Brushford, near Dulverton, where the beds may 

 be examined. Top Orchard Quarry, a mile and a quarter north 

 of Barnstaple, is a well-known locality for fossils. 



South of Barnstaple the Pilton beds appear to pass gradually 

 upwards into the Culm-measures, but owing to the absence of 

 sections, as remarked by Mr. Ussher, they make a most unsatis- 

 factory junction with these newer rocks, frequently exhibiting con- 

 trary dips in their vicinity, which are probably due to inverted 

 anticlinals. Moreover, where the junction should occur, the line 

 coincides with a strip of old Alluvial land. Near Dulverton Station 

 the distinction between the Pilton and Culm-measure slates appears 

 to be purely palceontological, and south of Clayhanger and Stawley 

 there is every reason to conclude that their junction is perfectly 

 conformable ; but at Morebath fault-junctions complicate the 

 relations of the beds.^ 



The slates in Lundy Isle may perhaps be on the horizon of the 

 highest Devonian beds, but their precise age is uncertain.* 



It will be remembered that Mr. Jukes regarded the red sandstones of the 

 northern portion of the Quantock Hills, those of Dunster, Minehead, and 

 Porlock, as of Old Red Sandstone age. The slates of Lynton, Ilfracombe, etc., 

 he grouped with the Carboniferous Slate ; while the sandstones of Pickwell 

 Down, Haddon Down, and Main Down, he regarded as probably a repetition of 

 Old Red Sandstone brought up by a concealed fault ; and he considered that the 

 overlying slates of Marwood, Braunton, and Pilton again represented the Car- 

 boniferous Slate which passed gradually upwards into the Culm-measures.^ Mr. 

 A. Champernowne observes, "Neither by fault, nor inverted junction along the 

 line indicated by Jukes, is there any wholesale reduplication of the North Devon 

 Series. The fault I had already taken to be disproved by Mr. Etheridge's 

 paper; "* and no evidence of it was found by Mr. Ussher in his more detailed 

 mapping of the area. 



1 G. Mag. 1881, p. 447. 



* T. M. Hall, Trans. Devon Assoc. 1871. 



^ Q. J. xxii. 320 ; Additional Notes on the Grouping of the Rocks of North 

 Devon and West Somerset, 1867 ; Notes on Parts of South Devon and Cornwall, 

 (R. Geol. Soc. Ireland), 1868. Reprint, p. 39. 



* G. Mag. 1879, p. 125. 



