notable being at Banwell, Harptree, and Burrington; and a large one has been recently discovered some 4 m. from Wells.  At Cheddar their W. edge is broken by a remarkable gorge, in the sides of which caves also occur.  The level of the tableland is indented with “swallet holes,” the chief of which are the East Water Swallet and the Devil’s Punch-Bowl.  The Quantocks are much less extensive, though their highest summits rise to a greater altitude.  Like the Mendips, they turn their steepest flank westwards, the ascent on the E. being gradual; and on this side they are cut by a number of well-timbered and delightful combes.  Few caves have been discovered in them, though there is one at Holwell near Asholt.  W. of the Quantocks are the Brendons and the highlands of Exmoor, the latter extending into Devon, though their highest point, Dunkery Beacon, is included in Somerset.  Dunkery is 1707 ft. above the sea-level; and other conspicuous hills in this district are Lucott Hill (1516), Elworthy Barrow (1280), Selworthy Beacon (1014), and Grabbist Hill.  The Quantocks, Brendons, and Exmoor consist of older rocks than the Mendips, belonging as they do to the Devonshire series of old red sandstones.  Bordering the Brendons are found the red marls of the Permian series; whilst between Dunster and Williton, and along the base of the Quantocks, in the neighbourhood of Taunton Dean, as well as in some other localities, Keuper and Rhaetic beds occur.  The Blackdowns in the S.W. are not quite so elevated as their neighbours; near Otterford and Chard they consist of greensand, whilst chalk appears at Combe St Nicholas and Cricket St Thomas.  The centre of the county is alluvial, and beneath it the limestone of the Mendips sinks, coming to the surface again in the W. only at a single spot, near Cannington.  Out of this central plain rise several isolated, cone-like hills, the most notable being Glastonbury Tor and Brent Knoll.  These belong to the lias and lower oolite rocks.  The Poldens consist of lias; and the same formation constitutes the rising ground that bounds the plain on the S. and E. of the county.  The southern side of the Poldens is edged with Rhaetic beds, which also extend to High Ham.  Oolite rocks occur abundantly near Bath, furnishing the famous Bath building-stone; and they likewise form the prominent eminence of Dundry.  Near Frome they rest upon the mountain limestone.  The same series of rocks occupies the S.E. corner of the county, extending from Milborne Port to Bruton.  On the E. they are flanked with the Oxford clay, which reaches from Henstridge to Witham Friary, whilst a ridge of higher ground near Penselwood consists of greensand.  Near Radstock coal is found.