T H A 



279 



T H A 



head of the Churn (or true Thames'), about three miles 

 south of Cheltenham : and from thence north-north-east 

 along- by the same hills to the head of the Windrush near 

 Carapden, and by Long- Compton Hill and Edge Hill to 

 the Arbury hills near Daventry at the northern extremity 

 of the basin. Here the basin of the Thames is contermi- 

 nous with that part of the basin of the Severn which is 

 drained by its affluent the Warwickshire Avon. 



From the Arbury hills the boundary of the basin runs 

 south to the neighbourhood of Bicester, and thence east- 

 ward across Buckinghamshire, Bedfordshire, and Hertford- 

 shire, along the Dunstable, Luton, and Royston downs, to 

 the north-western corner of Essex ; the basin of the Thames 

 being throughout conterminous with that of the midland 

 or Norfolk Ouse. This part of the basin of the Thames is 

 drained by its affluents, the Chanvell, the Thame, and the 

 Lea. An irregular line drawn through the county of Essex 

 from its north-western corner, first south-south-east by Dun- 

 mow and Brentwood. and then east by Rayleigh and Roch- 

 ford to the coast, will complete the boundary. 



The greatest extent of this basin from east to west is 

 from the mouth of the Thames to the neighbourhood of 

 Tetbury, about 136 miles ; the greatest extent from north 

 to south is fiom the neighbourhood of Daventry, Northamp- 

 tonshire, to the neighbourhood of Alton, Hants, about 78 

 miles. The basin comprehends the whole or part of 

 the following counties ; its area may be estimated as 

 follows : 



Sq. Mil. 



Kent ^'considerably more than half the county ; 



the western part) . . . 900 



Surrey (the whole county with the exception 

 of some small portions along the southern 

 border; ... . 7(1) 



Sussex fa small parl alonir the northern border) 3<X1 

 Hants (the northern and north-eastern part) . 350 

 Berks (the whole county ) . . . 750 



Wilts (the northern and north-eastern part ) . 450 

 Gloucester the south-eastern and eastern part) 450 

 Warwickshire ('a very small portion along the 



south-eastern border . . .50 



Northamptonshire 'a very small portion along 



the south-western border) . . SO 



Oxon (the whole county, with the exception of 

 two small portions on the north-eastern and 

 north-western bord . . . 650 



Bucks 'two-thirds of the county ; the central 



and southern part) .... 500 

 Bedford (a small portion at the southern extre- 

 mity . . . . 50 

 Herts (the whole county except some portions 



along the north-eastern border , . . 550 



Middlesex the whole county , . . 300 



Essex 'about one-third of the county; the 

 western and southern bon i . . 550 



Total 6600 



We liavc used round numbers, as in such an estimate an 

 approximation to the truth is all that can be attempted. 



The basin of the Thames is occupied wholly by the 

 idary ami tertiary geological formations. The sources 

 of the river and the course of its upper waters are in the 

 oolitic beds of the Cotswold hills. The valley through 

 which the Thames itself flows from above C'ricklade to 

 below Oxford is occupied by the Oxford clay, and between 

 Oxford and Goring (a little below Wall ingford; the river 

 flows over the formations (the coral rn<r, AyK'sbury stone, 

 Tetsworth clay, and greensand and chalk marl) which inter- 

 vene between the oolific and cretaceous groups. It traverses 

 the chalk range between Ilsley Downs and the Chiltern Hills 

 by;' winding valley, in which it flows from Goring to Maiden- 

 head, below which it enters the chalk basin of London, and 

 mainder of its course through it. The affluents 

 which join the Thames above Oxford have their course chiefly 

 in the oolitic disl rict ; the Thame and the Ock flow through 

 the district occupied by the groups between the oolites and 

 the chalk ; and of the remaining affluents, those which 

 join it on the north bank chiefly rise in the chalk hills, 

 and have their course in the chalk basin of London : while 

 ' of those which join it on the south bank rise in the 

 districts occupied by the subcretaceous formations, and 

 enter the chalk basin of London by openings in the chalk 

 range of the North Downs. Owing to the entire absence 



of coal, the basin of the Thames has no manufactures ex- 

 cept those of the metropolis ; but it contains some of the 

 richest agricultural districts in the whole kingdom. 



Course and Affluents. The spring which has com- 

 monly been regarded as the head of the Thames is about 

 three miles south-west of Cirencester, near a bridge over 

 the Thames and Severn canal which is called ' Thames- 

 head bridge ;' but that which is to be regarded as the true 

 head of the Thames is about three or four miles south of 

 Cheltenham. Two streams rise, one from fourteen springs 

 at what is popularly called The Seven Wells, and the other 

 from four springs near Ullen Farm, the westernmost of 

 which springs is the real (i.e. the remotest) head of the 

 river : both streams rise on the south-eastern slope of the 

 Cotswolds, and form by their junction, about a mile from 

 their respective sources, the river Churn (a name the ele- 

 ment of which is embodied both in the antient and modern 

 name of the town of Cirencester (the Corin-ium of the Ro- 

 mans), by which it flows ; and in the name of two villages, 

 North and South Cern-ey, which are near it. At Cricklade, 

 19 or 20 miles south-east from its source, the Churn joins 

 the commonly reputed Isis or Thames, the length of which 

 above the junction is only about 10 or 11 miles. 



From Cricklade the river flows 9 or 10 miles east-north- 

 east to Lechlade, receiving on the way the Ray (11 miles 

 long-) and the Cole (14 miles long), both on the south 

 bank. Just above Lechlade it receives on the north bank 

 a more important tributary, the Colne (23 miles long) from 

 the Cotswold hills east of Cheltenham ; and just below 

 Lechlade it receives the Lech, or Leach (19 miles long), 

 which also rises in the Cotswolds, and gives name to the 

 towns of North Leach and Lechlade. From Lechlade the 

 Thames flows 14 miles eastward to the junction of the 

 Windmsh, receiving accessions of small brooks on each 

 side. The Windrush rises in the Cotswolds bet ween Winch- 

 comb and Campden, and has a course of 34 miles by Bur- 

 ford and Witney ; it joins the Thames on the north bank. 

 Below the junction of the Windrush the Thames makes a 

 bend to the north and north-east, receiving on the north 

 bank the Evenlode, which rises in the Cotswolds near 

 Moreton in the Marsh, and has a course of 31 miles by 

 Charlbury, and receives the Glyme which flows through 

 Woodstock and Blenheim park. The Thames then turns 

 south, and flows to Oxford, where it joins the Charwell. 

 From the junction of the Windrush to that of the Charwell 

 lhe length of the Thames is 13 miles. The Charwell rises 

 in the Arbury hills near Daventry in Northamptonshire, 

 and flows southward 44 miles by Banbury : it joins the 

 Thames on the left bank. 



From the junction of the Charwell the Thames flows 16 

 miles south-south-east to the junction of the Thame at 

 Dorchester, making however a considerable bend westward 

 to Abingdon, where it receives the Oek. This river rises 

 at the foot of the chalk hills of Berkshire, between Comp- 

 ton Beauchamp and Ashbuiy, and flows eastward 18 miles 

 into the Thames, which it joins on the right or south-west 

 bank : the Thame rises near Stewkley in Buckinghamshire, 

 between Winslow and Leighton Buzzard, and flows 39 

 miles south-west by the town of Thame into the Thames, 

 which it joins on the left or north-east bank. From Dor- 

 chester the course of the Thames is south-east 22 miles in 

 a winding channel by Wallingford to the junction of the 

 Kennet near Reading. The Rennet rises near Broad Hinton, 

 a village to the north of Marlborough Downs, flows south 

 to East Kennet, and then turning eastward flows by Marl- 

 borough, Hungerford, Newbury, and Reading into the 

 Thames, which 'it joins on the right bank : its whole course 

 is 53 miles. It receives the Lambourn and the Embourn 

 or Auboni. 



From the junction of the Kennet the Thames flows east- 

 ward though in a very winding channel, making first a 

 considerable circuit to the north by Henley, Great Marlow, 

 and Maidenhead to Windsor ; and then a considerable cir- 

 cuit to the south by Staines, Chertsey, Kingston, and Rich- 

 mond to Brentford, from whence it proceeds by Hammer- 

 smith Putney, and Chelsea to the metropolis. The distance 

 from the junction of the Kennet to London-bridge is TO 

 miles In this part of its course the Thames received several 

 feeders. The Loddon, 24 miles long, rises in the chalk 

 downs of North Hants near Basingstoke ; the Coin, 38 

 miles long, rises, under the name of the Ver, in the chalk 

 downs of Hertfordshire, and passes St. Albans, Watford, 

 Rickmansworth, Uxbiidge, and Colhbrook ; the Wey, 3G 



