4 ME. E. A. XEWELL ARBER OX THE EPPER [Feb. 1907, 



field on several expeditions, and has most energetically contributed 

 to the information contained in this paper. My hearty thanks 

 are due to Mr. E. Tidal, of Fremington, for the constant interest 

 that he has taken in the progress of the work, and for valuable 

 local information. To others, also resident in Devon, including 

 Mr. J. G. Hamling. F.G.S., I am under obligations for information 

 and other help. The cost of exploring the more remote regions, 

 especially on the borderland between Devon and Cornwall, was 

 defrayed by a grant from the Royal Society Government-Grant 

 Committee, and for this aid I would here acknowledge my great 

 obligations. 



I am indebted to my friend Mr. R. Kidston, F.R.S., for assist- 

 ance in the determination of some of the fragmentary plant-remains, 

 and to him I would return my sincere thanks. Dr. AYheelton Hind, 

 F.G.S., has rendered me great service by naming many specimens 

 of the Devonshire fauna. Finally, to Mr. J. A. Howe, F.G.S., I am 

 greatly indebted for an examination of certain calcareous rocks 

 described here. 



II. The Lithological axd Physical Characters of the Rocks. 



It was shown by Sedgwick & Murchison 1 that the Carboni- 

 ferous rocks of Devon, Xorth Cornwall, and West Somerset 

 occupy a great synclinal fold. This basin is somewhat rect- 

 angular in form. The northern margin, stretching from the 

 estuary of the Torridge and Taw, through Barnstaple, to the neigh- 

 bourhood of Bampton and Ashbrittle, is bounded by the Upper 

 Devonian beds of Xorth Devon and Somerset. On the east, 

 the Trias overlies them unconformably. Xo doubt the Triassic 

 rocks once covered the whole, or nearly the whole, of the basin, and 

 have since been largely denuded. A long tongue of Trias still 

 stretches westward, to the north of Exeter, through Crediton as 

 far as Hatherleigh, and outliers are found on the coast at Portledge, 

 and elsewhere in the basin. The southern margin of the Carboni- 

 ferous rocks, ranging from near Boscastle on the coast as far as 

 Exeter, is bounded in part by Devonian rocks, and in part by the 

 granitic intrusion of Dartmoor. The Carboniferous deposits crop out 

 against the northern margin of Dartmoor, and are also found on its 

 flanks, as Godwin- Austen- pointed out many years ago. The entire 

 western limit is washed by the sea, and a large portion of the basin 

 has been removed by marine denudation, the effects of which are 

 especially evident in Bideford and Bude Bays. It is with the 

 western boundary of the Upper Carboniferous rocks that we are 

 here chiefly concerned. 



Although the Carboniferous rocks throughout the basin are 

 almost everywhere highly folded, faulted, and contorted, the broad 

 features of the district are fairly regular and easily traced. The 



1 Sedgwick & Murchison (40). 



2 Austen (42) p. 458. 



