30 Origin of the Cheddar Cliffs. 



ORIGIN OF THE CHEDDAR CLIFFS. 



BY D. MACKINTOSH, l.G.S. 



The Mendip range of hills, in Somersetshire, presents a 

 striking instance of a truncated anticlinal fold or axis. 

 According to Professor Ramsay, a mass of strata nearly a 

 mile in thickness has been cut off from the summit by denu- 

 dation, exposing the old red sandstone in the middle, with the 

 carboniferous, or mountain limestone, dipping away on both 

 sides. The outcrop of the limestone, under the old red, has 

 been shaped into steep escai-pments, with cliffs at intervals. 

 A very remarkable line of upland cliffs runs from the Shute- 

 shelve pass (between Sidcot and Axbridge) to Longbottom 

 pass, and some distance beyond. It is here and there indented 

 by cliff-bound ravines which, were they to become partially 

 submerged, would differ very little in shape from inlets of the 

 sea. Nearly on a level with the summit of this line of cliffs, 

 there is an approximately horizontal table-land, which few 

 geologists would hesitate to regard as a " plane of marine 

 denudation." Beyond Longbottom pass, in a south-easterly 

 direction, this table-land becomes irregular, and its south-west 

 escarpment, facing the Cheddar plain, is indented with combes 

 which are more or less cliffy, especially at their inner termina- 

 tion. A formation of Permian conglomerate, which in most 

 places may be found fringing the base of the Mendip Hills, 

 runs into these combes, proving that they must have been 

 mainly excavated before or during the Permian period. The 

 trumpet-shaped mouth of the Cheddar ravine might be classed 

 among these combes, were it not that it must have been formed 

 at a subsequent period, for its floor, as well as sides, consists 

 of carboniferous limestone. This ravine, at first sight, suggests 

 the idea (not confirmed by farther inspection) of the limestone 

 ridge through which it passes, having been " rent in twain" 

 from the top to the bottom. 



The Cheddar ravine, though long celebrated, deserves some- 

 thing more in the way of description than the very brief 

 notices that have hitherto appeared. In the preface to a 

 legendary article in a late number of the Gentleman' s Magazine, 

 it is justly regarded as " one of the most gorgeous specimens 

 of rocky scenery to be found in Europe. . . . The eye 

 grows accustomed to Switzerland, but Cheddar is a continual 

 surprise."* The object of the present paper is to give some 



* In the Fenny Cyclopedia it is alluded to as follows : — " . . . the defile 

 of Cheddar cliffs, with its long line of stupendous mural precipices, certainly 

 among the most magnificent objects of this kind in Britain. . . ." 



