HANGMAN GRITS. 125 



In the Lyn Valley, according to ]Mr. Ussher, the Valley of Rocks 

 owes its features in part to the even-bedding and jointing of the 

 grits in the Lynton Slates, and to the associated schists, which are 

 full of calcareous films ; and in part to the low dip of the strata. 



The Lynton Slates extend from Lynmouth to Woodabay, where 

 they are overlaid by the Hangman Sandstones. The slate rocks 

 overhanging Watersmeet, east of Lynton, are extremely rich in 

 fossils, some beds, as Mr. Etheridge has pointed out, being entirely 

 composed of Orthi's atruata. 



Hangman Grits. 



This group derives its name from the Little Hangman Hill near 

 Combe Martin. It consists of hard red and grey spotted grits, 

 quartzose sandstones, and shales. According to Mr. Ussher, the 

 upper beds are very coarse quartzose grits, with silvery red-stained 

 shales sometimes intercalated ; the lower beds are generally grey 

 flaggy or slaty grits, which pass down insensibly into the Lynton 

 Slates. The Hangman Grits attain a thickness of about 1500 feet. 

 Fossils are rare. In the upper gritty beds casts of Myalina, 

 CiiciiUcBa, etc., have been met with ; also Favosites cervicornis. 



The Hangman Grits may be studied on the coast west of Lynton, 

 where they overlie the Lynton Slates, at Woodabay, and in the 

 picturesque defile of Heddon's Mouth. The rocks were termed 

 the Martinhoe Beds by John Phillips, from their occurrence near 

 that village, and they were termed the Trentishoe Beds (or 

 Trentishoe flinty slate) by the Rev. D. Williams. 



The resemblance between the Hangman Grits and the Lynton 

 Sandstone, to which attention has been called, was remarked by 

 IMr. Etheridge. The Rev. H. H. Winwood has also made known 

 the occurrence of fossils in the sandstones of Alfoxton and Holford, 

 in the Quantock Hills, which correlate them with the Hangman 

 Grits ; and he concluded that the sandstones at the base of this 

 range of hills may be of the same age.' The Hangman Grits are 

 developed at Will's Neck, the highest point in the Quantock Hills, 

 and they occur at Dunkerry Beacon in the Exmoor Hills. At this 

 latter locality they were termed the Dunkerry Sandstone by the 

 Rev. D. Williams. 



Iron ore occurs along the junction of the Hangman Grits and 

 Lynton Slates at West Challacombe. 



MIDDLE DEVONIAN. 

 Ilfracombe Beds. 



These beds, to which the term Ilfracombe Group was applied by 

 John Phillips, are well developed in the neighbourhood of the town 

 from which they take their name. They consist of "calcareous 



1 Proc. Bath Nat. Hist. Club, ii. 427. 



