ORIGIN OF THE LEA VALLEY. 153
in the Lockwood Reservoir fairly well established the existence
of pile erections of the lake-dwelling type.
(b.) Sites like Edmonton, Tottenham, and Old London,
where gravels yielded water and dry foundations, determined
the earliest villages.
(c.) The high ground, so good for routes, was equally
suitable for villages. Hence we find very many places along
the roads, e.g., Leytonstone, Wanstead, George Lane, Woodford
Green, Woodford Wells, Buckhurst Hill along the Stratford—
Loughton road, and Stoke Newington, Tottenham, Edmonton,
Ponders End, Enfield Wash, Waltham Cross, Cheshunt along
the road to Ware.
(d.) The variety of soils and of surface features has led to
the development of route centres, markets and administrative
centres. The fords, the road junctions and the "gap towns"
are good examples of route centres. Markets are usually on
transitional land between two river systems or where two types
of country meet. (Stratford is the meeting place of forest
and river lowland, and Epping lies between the Lea and the
Roding.) Administrative centres have access to a wide area.
The best example, Hertford, still has its sign of authority in its
castle, where the present town council meets.
The disadvantages of the Lea Valley are few. Two great
handicaps are clay and marsh. Both of them encourage the
formation of fogs, which human ingenuity has not yet over-
come. The clay makes travel difficult because it is heavy in
winter and often baked hard and rough in summer. It is,
therefore, bad for road construction, and is not the best
foundation for houses, since it is so liable to slip. Modern
invention has conquered difficulties, and some of our healthiest
areas are on the London Clay.
The marsh was a barrier for a long time. Then man
gradually drained the Lower Valley and made reservoirs which
further reduced the liability to flooding. Means of crossing
the river, even by ferry, were very scanty and have been but
slowly improved. To-day this historic barrier is still evident
(especially during a railway strike, when the scarcity of roads
is so well brought home to dwellers on the Essex shore). The
bulk of west to east traffic goes by two routes, Lea Bridge Road
and the old Roman road at Bow. Even as late as 1919 the Lea