Physical Structure and older stratified Deposits of Devonshire. 643 



The beds of the great double group, just described, range across North 

 Devon, along with the calcareous system on which they rest, and are finely 

 exposed in the cuttings of the new road from Minehead to Dulverton, where 

 they agree so well with the corresponding parts of the coast section, that nearly 

 the same description might serve for both localities. The upper arenaceous 

 beds are well seen in the river gorges to the north of Dulverton. We have 

 not traced this system further to the east; but it appears to range through 

 Brandon Hill, and the elevated ground on the south side of the calcareous 

 bands of Croydon Hill, towards the plain of the new red sandstone. 



The fifth and last group of the northern region of Devon, commences on the 

 coast, in the headland called Baggy Point, where the beds dip S.S.W. at a 

 great angle. Many of them are composed of an arenaceous and siliceous flag- 

 stone, of a brownish gray colour ; but they are neither so thick nor so firm in 

 texture as the siliceous beds of the lower group, and are distinguished from 

 them also by ferruginous earthy bands, with numerous casts of organic re- 

 mains, which are wanting in the former. In rounding Santon Down, we find 

 a system of brown earthy slates and flagstones thrown into a succession of vio- 

 lent undulations ; but on skirting the marshes still further towards the south, in 

 the direction of Barnstaple, they acquire a steady dip to a point about south 

 by west ; and with the same dip, they are seen in some low earthy cliffs oppo- 

 site Fremington Pill, near Barnstaple, on the south side of the river, and 

 are thereby carried under the base of the great culmiferous series. 



By referring to the accompanying Map, it will be seen, that the breadth of 

 this fifth group, near the coast, measured on a line perpendicular to the strike, 

 is not less than three or four miles. Following its range towards the east, it 

 is seen underlying the culmiferous rocks to the north of South Molton ; and 

 the upper portion of it passes under the same rocks between Dulverton and 

 Ex Bridge. (See Sect. fig. 4. PI. LI.). Still further in the prolongation of the 

 line of strike towards the east, the mineral character of the group undergoes 

 a considerable change. The brown and gray arenaceous flagstones of its in- 

 ferior portion, often pass into a red sandstone, hardly to be distinguished from 

 the red sandstone of the second group; and its upper portion at the same time 

 passes into a beautiful bright red and variegated earthy slate, which underlies 

 the culm series, and is well exposed in a rivulet between Trace Bridge and 

 Stawley. Considered as a whole, this fifth group is distinguished by its lower 

 arenaceous flagstones, with ferruginous bands of rottenstone, full of organic 

 remains ; by the dull colour and more earthy texture of its slaty beds; by its 

 brown flagstones, covered with impressions of encrinital stems ; by its calca- 

 reous bands, sometimes passing into great lenticular masses (provincially called 



VOL. V. SECOND SERIES. 4 O 



