352 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Mai. 7, 



red ferruginous matter, 20 or 30 feet in width, striking steadily 

 with the strike of the rocks, but dipping south at much higher 

 angles. The rocks dip south at angles gradually increasing from 5° 

 to 30°, but the red ferruginous bands are inchned at angles of 50° 

 or 60°. The rock thus stained red externally, is dark grey when 

 first broken open, but the red ochre is in such quantities, and so 

 readily stains the hammer and the fingers, that even a fresh fracture 

 is apt to get raddled soon after it is broken, if precautions are not 

 taken to prevent it. 



These red ferruginous bands are very deceptive when viewed from 

 a little distance, and especially when seen from a boat, as they look 

 precisely like beds of red rock, and have, I believe, been taken for 

 such beds by some previous observers. 



I believe I detected the origin of the ochre, at the cove of Heddons 

 Mouth, in little plates and strings of hsematite in the quartz veins 

 there. These quartz veins traversed certain beds of rock in great 

 quantity without penetrating beyond them, either above or below ; 

 and the haemitite occurring as nests in their cavities would when 

 weathered be naturally converted into red ochre. 



I also observed at Heddons Mouth a mass of grey grit, curiously 

 marked on the surface with wavy interrupted lines or narrow bands, 

 like the edges of compressed cups of Fenestella in the Carboniferous 

 Limestone*, and on breaking open the rock, I found them to be 

 similarly due to undulating sheets of Fenestella, or of some closely 

 alKed form. 



The cleavage of the rocks from Lynton to Heddons Mouth dips 

 everywhere south or south-south-east, usually at an angle of 50° or 

 60°; but in two places, where the beds were horizontal, I find it 

 recorded in my note-book as dipping at as low an angle as 15°. 

 The beds at Heddons Mouth dip south at 20°; east of Woodabay the 

 angle increases to 30°, but as the shore bends to the north, the angle 

 flattens to 15° and 5°, and just west of Lynmouth the beds are 

 horizontal. I did not visit the headland east of this, under Countes- 

 bury, but from the deck of the steamer the beds seemed certainly 

 to dip at a high angle to the north, as drawn in Sir H. De la 

 Beche's sketch-section in the Report on Cornwall, Devon, and West 

 Somersetshire. 



Proceeding inland the beds undulate at gentle angles, as may be seen 

 in the vaUey of the East Lyne and elsewhere. A little farther south, 

 however, there appears to be a higher northern dip. Greenish-grey 

 grits and gritty slates dip north-west at 45° in the bed of the brook 

 near Sparhanger, and bluish grey slate and brown grits dip north- 

 north-west at 20° in some quarries near Brendon. If the rocks rise 

 to the south persistently for any distance south of this, the top of the 

 Old Red Sandstone will probably reach the surface. I did not see any 

 rock for some miles to the southward, except one small quarry near 

 Earley Common, where a brownish sandstone dipped south-west at30°. 



^ Mr. A. B. Wynne, now of the Indian Survey, first called my attention in 

 Ireland to the fact that these wavy markings were the edges of undulating sheets 

 and cups of Femstella. 



