LONDON BRIDGE, old, 21; avoidance of high gradient and result, 24; convergence of roads to, 25; effect of on development of the city, 29; function of in making an inland port, 30; lowest old bridge on the Thames, 97; and necessity of detours by Roman troops, 103; advantage of site of, 122 LYME REGIS, 98 LYNTON AND LYNMOUTH, gradients at, 42 LYONS, double crossing of streams at, 32; spread of Christian religion to, 70 MACADAM, 90; and the improvement of road surface, 189-90 MAESTRICHT, 29 MANCHESTER, 122 MARBLE ARCH and Watling Street, 164 MARSH, effect of on course of roads, 7-10; impassability of, 14-15; divided Lancashire from Southern England, 15; Thames estuarine, 15; protected Venice, 15; and Russian Church, 15; and Russian Revolution, 15; isolation of Gargano due to, 15; effect of on course of road from Pulborough to Arundel, 17; and Eastern and Western European civilisation, 15; at Bramber, 18; created by roads, 64-5; Pinsk, 76-7; of Thames estuary, 121-2; effect of on Roman roads, 103-4; formation of during Dark Ages by disrepair of Roman road at river crossings, 158-9 MARSHES, disappearance of section of Roman roads in during Dark Ages, 149-55 MATERIAL for road construction, influence of proximity on course and number of roads, 14, 52-5; diversity of in England, 105-6 MEDWAY, the, 19; crossing of at Snodland, 130; at Rochester, 130 MELUN, double crossing of streams at, 32 MENAI STRAITS, suspension bridge over, 188 MENDIPS, lead mines of, 98; trackway to, 120 MERSEY, RIVER, marshes of, 122 MERTON, gap in Roman road between Epsom race-course and, 149; and Stane Street, 166-70 MICHELHAM and Stane Street, 170 MIDDLE AGES, the, and bridge building, 22; and the bridge as a place of toll, 26; road system of, 114, 154, 177-8 MIDHURST, 131 MILITARY ROADS, Roman roads designed as, 133-7; in U.S.A., 75; on the Rhine, 75; Alpine, 75 MOLE, RIVER, 19; crossing of by Pilgrims’ Way, 131 MONTREUIL, 31 MOROCCO, effect of “nullahs” in, 36-7 MOSELLE, valley of, 44-6 MOTOR VEHICLE, the (_see_ Internal-combustion Engine) NAPLES, 70 NERO, 102 NEWCASTLE, bridge of, 97; function in making an inland port, 30 NEWHAVEN, swing bridge at, 99 _Nodal Points_, definition of, 26; creation of by bridges, 26-9; and military strategy, 29; and markets, 29-30 _Nore Wood_ and Stane Street, 51 NORFOLK, trackway to, 125; and Peddars Way, 174 NORMAN CONQUEST, the, and Sussex, 132 NORTHUMBERLAND, Roman wall in, end of road from Egypt, 70 NORTON PARK (Northants), example of marsh formation through breakdown of culvert, 158-9; map, 159 “NULLAHS,” effect of on road building, and example in Morocco, 36-7 OAKENGATES (Shropshire) and Watling Street, 164