SOMERSETSHIRE, a county in the west of England, is bounded N. by the Bristol Clutnnel, the meatuary of the Severn, and Gloucester shire; E. by Wiltshire; S. by Dureetshire and Devonshire; and W. by Devonshire. It lies between 50' 49' and 51' 30' N. hits, 2° 14' and 3 50' W. long. The longest line that can be drawn upon its surface from cant to west measures 68 miles, from north to south 43 miles. A portion of the county however, extending 38 miles westward from Bridgewater, has a mean breadth from north to south of only 13 miles. The area is 1E36 square miles, or 1,028,090 acres. The population in 1811 was 435,599; in 1851 it wax 443,916.
Surface, Coast-Line, and Geology.—Somereetshiro is a hilly county, and the ranges of hills are separated by low marshy flats. The north eastern part is occupied by the eminences round Bristol and Bath, through which the Avon makes its way to the Severn. These emi nences are irregularly grouped, and extend from Pill on the Avon, below Bristol, into Wiltshire : many of the valleys, called combes or coombs, which separate the hills, are drained by small feeder, of Avon. The principal heights iu this part of the county are—Falkland Knoll, near Norton St. Philip, between Bath and Frome; Lanselown (813 feet high), and Claverton, Combs, and Odd Downs, near Bath ; Dundry Hill, west of Keynaham (790 feet high); the summits of Broadfield Down, south of Bristol; and Leigh Down, west of that city. The summits of the hills in the immediate neighbourhood of Bath are of the oolitic formations. The great oolite furnishes the stone coin mooly known as Bath stoup. Sometimes the lower oolitic beds form outlying eminences, such as Stantonbury Hill, Dundry Hill, and Mays Knoll. The inferior °elite is extensively quarried iu Dundry Hill. The Dollies rest on a platform of the lies formations, which appear on the lowest part of the elope of the oolite hills, or form detached hills to the south-west of them.
The valleys of the Avon and its feeders are occupiei by the new red-sandstone formations, capped in some places by the newer mag nesian limestone, which crowns the hills or rests in horizontal strata against the elevated beds of the coal-measures or of the mountain limestone, which latter, with the old red-sandstone, forms the con stituent mass of Leigh and Broadfield Down, near Bristol. The mountain limestone of Leigh Down is prolonged across the Avon, and forms the well-known precipices of St. Vincent's rocks, Clifton, between which the Avon flows. Broadfield Down has two precipitous combes or valleys, Cleve and Brockley, less magnificent than the defile of Cheddar, but possessing, from the abundance of wood, more beauty. The coal-measures, mountain limestone, and old red-sandstone, belong to the carboniferous group of the Somersetshire and South Gloucester shire coal-field, and occupy the northern part of the county, extending to the Mendip' Hilli;though covered iu most places by more recent formations. In this field are numerous coal-pita.
The eastern side of the county, extending from Bath to Yeovil, and the southern side, from Yeovil to 'Wellington, are occupied by hills of similar geological character to those around Bath, and uuitiug with them near that city. This range is divided into detached parts by the transverse valleys of the Brue, the Yeo or Ivel, the Parrot, and the Isle. The vale of Taunton is occupied by the new red-sandstone. Good freestone is quarried in the inferior oolite near Shepton Mallet, and at Norton-under-Hamden ; and the Has is much used for building cottages in the neighbourhood of Ilchester.
The Mendip Hills are a distinct range, stretching from west by north to east by south, and separated from the hills about Bath and Bristol by the narrow valley of the Yeo, a small stream which flows into the Bristol Channel near St. Thomas's Head. They extend at their western end to the coast, and unite at their eastern extremity with the hills near Frome. The length of the Mendips is about twenty-five miles ; their breadth, between Stoke Rodney and West Harptree, six or seven miles. "This chain consists of a central axis of old red sandstone, flanked on its opposite declivities by parallel bands of mountain limestone, dipping from it in opposite directions in angles varying from 30° to 70°. This central axis is not however visible throughout its whole course, being occasionally over-arched and con cealed by the calcareous strata ; but it appears in four ridges, forming the most elevatel points of the chain, and disposed at nearly equal distances through its length. The cavern of Wookey Hole, and the defile of Cheddar cliffs, with its long line of stupendous mural preci pices, certainly among the most magnificent objects of this kind in Britain, are the well-known features of this chain." (Conybeare and Phillips). The mineral treasures of the Mendips are important ; zinc and calamine are obtained abundantly in the central and western part of the range. There are numerous coal-pits in the villages which lio north-west of Frome. The Mendips rise in some parts to more than 1000 feet. The long low ridge of Polden Hill is an offset from the eastern hills, extending about twenty miles in a direction parallel to the Mendips, from which it is separated by a wide fenny lint Gypsum occurs abundantly iu the red marl on the south aide of Polden Hill, near Somerton.