232 Messrs. Bucrland's and Conybeare's Observations on the 



dar cliffs, which rivals any of the wildest defiles in the highest mountains of 

 the British Islands *. 



To the west of the gorge of Loxton the double band of limestone becomes 

 united into a single saddle-shaped ridge, and is so continued to the extreme 

 western point of Bleydon-hill, near Uphill, at the mouth of the Axe, where the 

 chain gradually sinks to a level with the seaf . The strata dip on either side 



* We here insert some notes on the geology of this part of the Mendip hills, by the late Smith, 

 son Tennant, Esq., which have been communicated to us by Mr. Warburton. 



" Going westward from Cheddar along the foot of the mountain, you arrive at a rocky combt, 

 at the bottom of which on the eastern side the strata consist of magnesian limestone, and dip to the 

 south ; on the western side the strata have the same dip, but consist of common limestone. Higher 

 up the combe is seen a rugged mass of re-cemented magnesian limestone. The mass is triangular with 

 its point downwards ; it ascends only |ds of the slope of the hill. Is this mass part of a stratum, 

 or has it been washed here in fragments, and deposited on the surface of the limestone ? 



The next combe has masses of re-cemented magnesian limestone on its eastern side. Another gap, 

 which admits of a road from Shipham to Axbridge, has masses of the same rock on its Avestern side. 



The next break, which is by far the most considerable, admits the road from Bristol to Cross. 

 Regular strata of magnesian limestone, dipping to the south, are here cut through to let the road 

 run level. In quarries to the east of the road the rock is generally reddish, but sometimes co- 

 loured green by chlorite. It is filled with entrochi, and some imperfect and broken shells. The 

 shells and entrochi are not magnesian, but partly calcareous, partly siliceous. To the west are 

 quarries for mending the road, in which are masses of chert imbedded in magnesian limestone. 

 Above the level of the magnesian strata, both to the east and west, is blue limestone. Going 

 westward towards Crook's Peak, projecting strata of limestone and magnesian limestone are ob- 

 served ; the most western part of the Peak is principally magnesian limestone, of a dark grey co- 

 lour, and very hard. Crook's Peak terminates this southern ridge of the Mendips, but another 

 ridge which extends to the Bristol Channel lies a little to the north of the former. This northern 

 ridge consists of alternating strata of common and magnesian limestone. About 2 miles east of 

 Bleydon, near a lime kiln, the contact of the two rocks may be observed. The strata dip to the 

 south. Where the two rocks arc in absolute contact, there is a mutual intermixture of substance 

 to the depth of an inch or i»vo ; but fragments of the size of an egg may be obtained, in which the 

 two rocks are so distinct, that one side will be dissolved in acids rapidly, the other slowly. Sonif-- 

 llmes there is an interval between the two rocks, which is filled with red crystals of quartz. At 

 the distance of 1 mile from Bleydon the magnesian limestone is found of a dark blue or grey colour. 

 Near Bleydon are raised flattish blocks of a light buff-coloured re-cemented magnesian limestone, 

 consisting of that substance in the state of sand, including angular fragments of the blue variety 

 just mentioned. The paste is occasionally impure from an admixture of iron and clay ; the blue 

 parts in some places contain shells." 



f For an account of the cavernous fissure in mountain limestone at Hutton-hill on the northern 

 slope of this ridge, which, together with ochre, ochreous clay, and fragments of limestone, was 

 found to contain the bones of ante-diluvian animals, see Rpliqiiice Diluvianw, p. 57. At Ban- 

 well also ochre either is or has been dug in fissures of the limestone. In both these cases it seems 

 to be of diluvian origin. 



