Physical Structure and older stratified Deposits of Devonshire. 637 



spending section from Berry Head to Start Point. The upper beds of limestone are seen at 

 Mount Batten, and are overlaid by a great, red, arenaceous group, which may be subdivided as 

 follows : 



(1.) Over the limestone is a brown and yellow earthy slate, with pyritous stains and iron veins, 

 some of which run, in the form of strings, nearly north and south. This mass alternates three 

 times with beds of impure limestone ; and the last bed occurs at Dunstan Point, where it thins out 

 to an edge among the impure earthy slates. Several fossils have been found by Mr. Hennah in 

 this part of the section, which may be considered as forming a kind of passage from the limestone 

 to the superincumbent beds. 



(2.) From Dunstan Point to Withy Hedge, the section shows a yellowish gray and bluish gray 

 soft slate (shillat), with some quartz veins and coarse arenaceous bands. 



(3.) Immediately over the preceding, and extending about three-quarters of a mile to Bovisand 

 Bay, is a formation of bright red, and sometimes variegated sandstone, thick-bedded, and of 

 coarse texture, but subdivided by bands of soft, glossy, red slate, and red micaceous flagstone. 

 This division, in many parts, is exactly like the old red sandstone; and though thrown into vio- 

 lent contortions, it dips, on the whole, towards the south, and is of great thickness. It is overlaid 

 by a reddish slate and flagstone, which gradually passes into the next superior division. 



(4.) On the south side of Bovisand Bay, the slates become so earthy as to pass into the form of 

 shale, with many small nodules of ironstone ; and these are surmounted by variously-coloured 

 earthy slates, alternating with reddish arenaceous bands, as seen in the cliffs of Crownall Bay, 

 near the southern end of which is a patch of new red conglomerate, resting unconformably on the 

 edges of the older strata f. 



(5.) Beyond Crownall Bay is reddish slate and flagstone, and coarse red sandstone, occasionally 

 contorted and penetrated by large quartz veins ; the contortions chiefly seen in the strongest and 

 coarsest beds. These gradually pass into reddish, grayish, and greenish gray chloritic slates, with 

 hard quartzose bands and quartz veins. They strike about E. by N. towards Wembury, are of 

 great thickness, and may be considered as beds of passage into the next superior group. 



Though the upper limit of the preceding group is ill-defined, it is, on the whole, very distinctly 

 marked by its coarse arenaceous bands and its prevailing red colour : and as its breadth, measured 

 on a line transverse to the strike (from Mount Batten to the cliffs opposite the Mew Stone), is 

 about three miles, and its average dip is not less than 35°, its thickness (notwithstanding the occa- 

 sional contortions) mi^st be very great. In its mineralogical characters, as well as in its thickness, 

 it bears the closest resemblance to the red arenaceous rocks in the cliffs east of Combe Martin, 

 the second group of our North Devon section. 



2. The next group occupies the whole coast, from the cliff's opposite the Mew Stone to Hope 

 Cove, near Bolt Tail — a distance, following the sinuosities of the coast, of more than twenty miles ; 



coast section are referred by a series of lines drawn, from the respective points, parallel to the 

 strike. Most of the places mentioned are found on the accompanying Map, PI. L. 



f Soon after our return from Devonshire, in 1836, we were informed by Dr. Moore, of Ply- 

 mouth, that he had discovered organic remains in this part of the series. One of the authors 

 revisited, along with that gentleman, this part of the coast in 1838. The fossils chiefly occur in 

 the ironstone nodules, and are generally both obscure and waterworn. We remarked among his 

 specimens a Turbinolia(l), and several other species of corals ; two or three species of Orthocera- 

 tites; one or two casts of univalves ; and some fragments of trilobites. Among the red cliflTs of 

 Crownall Bay, only to be approached at low water, are also many fossils, such as stems of Encri- 

 nites, fragments of corals, and comminuted shells, in an impure bed of reddish limestone, partly 

 traversed with quartz veins. Near the calcareous bands were some transverse planes of slaty 

 cleavage — appearances very rare in this part of Devonshire. 



