H. B. Woodward — Inversion of Carboniferous Strata. 457 



taken place. And we cannot yet explain, where so mucb has been 

 denuded, why these masses of Limestone remain." 



As I have elsewhere remarked, in considering this somewhat diffi- 

 cult subject, it must be borne in mind that the structure of the 

 Mendip Hills is not that of one simple anticlinal fold dipping to the 

 north-east and south-west, and trending north-west and south-east ; 

 but that the structure displayed comprises a number of folds, which 

 trend in an easterly and westerly direction, and which are products 

 of that line of upheaval, which, only when looked at in a large way, 

 can be termed the " Mendip Anticlinal." ^ 



Thus immediately north of Shepton Mallet, and in a line between 

 Cheylinch and Bowlish, there is evidence of an anticlinal ; and it is 

 probable that this is the continuation of one noticed north of Leigh- 

 ton, which is, however, displaced by a fault. 



A second anticlinal extends from near Frome, by Little Elm and 

 Downhead, to Masberry Castle, and is continued through Lyat Hill. 



A third anticlinal is met with at Pen Hill, and thence continues 

 westwards to the Ebber Eocks, and in a north-easterly direction to 

 Lechmere Water,' near Emborrow. The beds are much faulted ; at 

 Ebber and Pen Hill House, the Old Bed Sandstone is brought against 

 the Carboniferous Limestone, and at Emborrow it comes in contact 

 with the Millstone Grit. These faults are of great magnitude, the 

 amount of displacement at the last-named locality being probably at 

 least 3,000 feet. 



A fourth anticlinal runs from North Hill westwards through Stoke 

 Warren, and probably accounts for the trace of Old Ked Sandstone 

 which my colleague, Mr. Blake, considered to be faulted against the 

 Carboniferous Limestone about a mile south-east of Cheddar. Here 

 again is another fault of great magnitude. 



A fifth anticlinal, that of Black Down, is continued through Bleadon 

 Hill to the Steep Holme. This islet, as is well known, exhibits an 

 inverted anticlinal of Carboniferous Limestone, the strata being bent 

 over in a northerly direction ; and this feature is repeated at Dolberry. 



So that if we constructed a longitudinal section through the 

 Mendip Hills, we should find the structure to consist of a number 

 of anticlinals, locally faulted and inverted. And it is the prolonga- 

 tion of these known disturbances into the Coal-measures that must 

 help to account for the great dislocations and contortions that affect 

 them. We can scarcely expect to trace their continuation with 

 exactness in these newer and more easily contorted strata, and in 

 the Nettlebridge Valley the amount of confusion which the Coal- 

 measures present is so great, that Mr. McMurtrie remarks it would 

 baffle description. The Eadstock slide-fault is likewise a remarkable 

 instance of local disturbance. Nor must the evidence of another 

 considerable fault be neglected, and this is the one which runs from 

 Beckington to near Mells, and whose natural continuation would be 

 to Vobster. Along this line of fault a trace of Old Eed Sandstone is 

 brought to the surface north of Frome, as first represented by Lonsdale.^ 



^ See Memoir on the Geology of East Somerset and the Bristol Coal Fields, 

 p. 196. 2 Trans. Geol. Soc. 2nd ser. vol. iii. plate 32. 



