Page:Encyclopædia Britannica, Ninth Edition, v. 14.djvu/47

 KENT 37 and S.E. by the English Channel, S.W. by Sussex, and W. by Surrey. Its greatest breadth north and south from Sheerness to Dungeness is 35 miles, its length north-west to south-east from London to Dungeness about GO miles, and its length west to east from Surrey to North Foreland in Thanet 65 miles. The area is 1,004,984 acres, or 1570 square miles. Coast Line. About two-thirds of the boundary line of Kent is formed by tidal water. The estuary of the Thames may be said to stretch from London Bridge to Sheerness in the Isle of Sheppey, to the north-west of which the estuary of the Meclway cuts off a tongue of land whose extremity is termed the Isle of Grain. Along the banks of the Thames the coast is low and marshy, embankments being in several places necessary to prevent inundation, [n the estuary of the Meclway there are a number of low marshy islands, but Sheppey presents to the sea a range of chalk cliffs from 80 to 90 feet in height. The marshes extend along the estuary of the Swale to &quot;Vhitstable, whence stretches a low line of clay and sandstone cliffs, succeeded at the Isle of Thanet by the white chalk cliffs which extend southwards to Pegwell Bay. The coast from Sheppey round to the South Foreland is skirted by numerous flats and sands, the most extensive of which, the Goodwin sands, forming the breakwater of the well-known anchorage of the Downs, are said to have formed part of the estate of Earl Godwine, and to have been submerged as late as 1097. From Pegwell Bay to near Deal the outline of the coast is flat, but thence it rises again into chalk cliffs, which continue round the South Foreland to Folkestone, where they are succeeded by the flat shingly shore bordering Romney Marsh. A considerable portion of Romney Marsh has been reclaimed from the sea since the time of Julius Caesar, but in nearly every other portion of the coast the sea has been gaining on the land. Surface and Geoloyy. -Kent abounds in beautiful and finely-wooded valleys with undulating and picturesque up lands. A tract from 7 to 8 miles broad lying to the south of the estuary of the Thames, and extending eastwards as far as Thanet, belongs to the London Tertiary basin, and is formed chiefly either of London or of plastic clay. The London Clay occupies the tongue of land between the estuiries of the Thames and Meclway, as well as Sheppey and a district of country about 8 miles wide stretching southwards from Whitstable to Canterbury, and extending eastwards to the Isle of Thanet. It reappears at Pegwell Bay, and in the neighbourhood of London it rises above the plastic clay into the elevation of Shooter s Hill, with a height of about 450 feet, and a number of smaller emi nences. The thickness of the formation near London is about 400 feet, and at Sheppey it reaches 480 feet. At Shappcy it is rich in various kinds of fossil fish and shells. The plastic clay, which rests chiefly on chalk, occupies the remainder of the estuary of the Thames, but at several places it is broken through by outcrops of chalk, which in some instances run northwards to the banks of the river. The Lower Tertiaries are represented by three different formations known as the Thanet beds, the Woolwich and Reading beds, and the Oldhaven and Blackheath beds. The Thanet beds resting on chalk form a narrow outcrop rising into cliff s at Pegwell Bay and Reculvers, and consist (1) of a constant base bed of clayey greenish sand, seldom more than 5 feet in thickness ; (2) of a thin and local bed composed of alternations of brown clay and loam ; (3) of a bed of fine light buff sand, which in West Kent attains a thickness of more than 60 feet ; (4) of bluish grey sandy marl containing fossils, and almost entirely confined to East Kent, the thickness of the formation being more than 60 feet ; and (5) of fine light grey sand of an equal thickness, also fnssiliferous. The middle series of the Lower Tertiaries, known as the Woolwich and Reading beds, rests either on the Thanet beds or on chalk, and consists chiefly of irregular alternations of clay and sand of very various colours, the former often containing estuarine and oyster shells and the latter flint pebbles. The thickness of the formation varies from 15 to 80 feet, but most commonly it is from 25 to 40 feet. The highest and most local series of the Lower Tertiaries is the Oldhaven and Blackheath beds lying between the London Clay and the Woolwich beds. They consist chiefly of flint pebbles or of light-coloured quartzose sand, the thickness being from 20 to 30 feet, and are best seen at Oldhaven and Blackheath. To the south the London basin is succeeded by the North Downs, an ele vated ridge of country consisting of an outcrop of chalk which near Westerham on the borders of Surrey reaches an elevation of 812 feet above sea-level, and at several other places more than 600 feet. It extends from Wes terham to Folkestone, with an irregular breadth generally of from 3 to 6 miles, but expanding to nearly 12 miles at Dartford and Gravesend and also to the north of Folke stone. After dipping below the London Clay at Canterbury, it sends out an outcrop which forms the greater part of Thanet, and towards the sea is often broken off into pre cipitous escarpments. To the south of the Downs there is a narrow valley formed by the Gault, a fossiliferous blue clay. This is succeeded by an outcrop of the Lower Greensand, which extends across the country from west to east with a breadth of from 2 to 7 miles, and rises into the picturesque elevations of the Ragstone hills. These in several cases reach a height of over 600 feet, and have a steep slope southwards, overlooking the valley which extends from the borders of Sussex to Hythe. This low ground is occupied chiefly by the Weald clays, which con tain a considerable number of marine and freshwater fossils. Along the borders of Sussex there is a narrow strip of country consisting of picturesque sandy hills, whose highest elevation is nearly 400 feet ; and the south-west corner of the county is occupied by Romney Marsh, which within a comparatively recent period has been recovered from the sea. The London Clay is much used for bricks, coarse pottery, and Roman cement. Lime is obtained from the Chalk and Greensand formations. Ironstone is found in the Wealden clays and calcareous ironstone in the Ashdown sand, but the industry has long been discontinued. The last Wealden furnace was put out in 1828. Rivers. The Thames, which forms the northern boundary of the county, receives the Ravensbourne at Deptford, and the Darent or Dart, which has a course of 18 miles, and becomes navigable at Dartford. The Medway, which has a course of over 50 miles, and with its tributaries drains a basin having an area of GSO square miles, is formed of several streams that rise in the neighbourhood of Tunbridge Wells, and of East Grinstead in Sussex. After passing Ashurst and Penshurst it receives the Eden from the west, and at Yalding in the Weald the Teise and Beult. At Chatham it widens into an estuary, the greater portion of its waters ultimately joining the Thames at Sheerness, and the other portion passing southwards to the sea through the Swale Channel. The river is tidal as high as Maidstone. The Stour, which has a course of nearly 50 miles, and with its tributary the Little Stour drains an area of about 380 square miles, has its origin in several streams which spring from the Lower Greensand and the Chalk, the two main branches, which have their source near Lenham and near Hythe respectively, uniting at Ashford. At Sarre the Stour separates into two branches which insulate the Isle of Thanet, the smaller portion flowing northward to the sea near Recnlver, the other and main portion flowing eastward to Pegwell Bay. The stream is tidal and uavig-