Yol. 6$.~\ CARBONIFEROUS ROCKS OF DEVON AND CORNWALL. 15 



I may now give some account of the distribution of these 

 concretionary beds in the Upper Carboniferous rocks of Devon and 

 Cornwall ; commencing in North Devon, and passing westward and 

 southward into Cornwall. 



In 1876 the late Townshend Hall 1 described the occurrence of 

 nodular beds, containing goniatites and lamellibranchs, at Instow, 

 some 3 miles to the north of Bideford, and at the same time 

 announced the discovery by Mr. W. Porter, of Pilton, of a specimen 

 of Ccelacanthus elegans (Newb.) from the same beds. At a later 

 period, another fish, Elonicliiliys Aitkeni, Traq., was found in this 

 locality. These specimens, all of which are now in the British 

 Museum (Natural History), remained the only fossils known from 

 the Upper Carboniferous of North Devon, with the exception of 

 plant-remains, until the beginning of the present enquiry in 1903. 



The Instow beds have been again examined on several occasions. 

 The)' lie almost in a direct line with the mouth of the estuary of 

 the Torridge and Taw, rather less than a mile distant, along the right 

 bank of the former river, from Instow Station. The nodule-beds are 

 uncovered only near low water, and at present are much obscured 

 by sand and seaweed. The nodules, although usually washed out 

 by the scour of the tidal river, no doubt occur in definite beds of 

 shale, as in other districts. They are found on either side of a low 

 and much denuded anticline. Nodules containing Gastrioceras 

 carbonarium (von Buch), Dimorphoceras Gilbertsoni (Phill.), and 

 Pterinopecten papyraceus (Sow.), may still be obtained in the 

 neighbourhood of this fold, but fish-nodules are now very rare, and 

 probably were always scarce. Mr. Rogers, however, has had 

 the good fortune to discover a fine and almost perfect specimen of 

 Ccelacanthus elegans (Newb.) in excellent preservation, of which 

 there are only two other examples known from Devon. The fish- 

 nodules are tougher and more compact in texture than the ordinary 

 calcareous nodules, although they contain enough lime to effervesce 

 freely with acid. The only plant-remains found at Instow are 

 imperfect fragments occurring in some of the shell-nodules, chiefly 

 obscure Calamite-casts. 



Calcareous nodules have also been found in Hubbastone Quarry 

 and at Appledore, 2 on the opposite side of the river Torridge. 

 Mr. Ussher 3 has already noticed the concretionary beds at the last- 

 named locality, and also along the coast-line towards Clovelly. 

 On the other hand, I have not observed any calcareous nodules 

 closely associated with the culm-bands of the Bideford district, 

 although De la Beche 4 speaks of nodules of argillaceous ironstone as 

 occurring with the so-called * anthracite ' (see p. 13). The nearest 

 concretionary beds to the culm-bands, with which I am acquainted, 

 are those at Cockington Head near the anticline described on p. 7, 

 which lies nearly a mile to the southward. Two beds of nodules, 



1 Hall (76). 



2 The names of localities mentioned here are all shown on the 6-inch 

 Ordnance Survey maps of Devon & Cornwall. 



3 Ussher (92) pp. 148-53. De la Beche (39) p. 125. 



