Other farm implements were: coulters, which gave free passage to the plough by cutting weeds and turf, picks, spades and shovels, reaping hooks and scythes, and sledge hammers and anvils. Strips of land for agriculture were added from waste land as the community grew. Waste lands were moors bristling with brushwood, or gorse, heather and wanton weeds, reed-coated marshes, quaking peat-bogs, or woods grown haphazard on sand or rock. With iron axes, forests could be cleared to provide more arable land. Some villages had a smith, a wheelwright, and a cooper. There were villages which had one or two market days in each week. Cattle, sheep, pigs, poultry, calves, and hare were sold there. London was a town on the Thames River under the protection of the Celtic river god Lud: Lud's town. It's huts were probably built over the water, as was Celtic custom. It was a port for foreign trade. Near the town was Ludhill. Flint workers mined with deer antler picks and ox shoulder blade shovels for flint to grind into axes, spearheads, and arrowheads. Mine shafts were up to thirty feet deep and necessitated the use of chalk lamps fuelled by animal fat with wicks of moss. The flint was hauled up in baskets. Common men and women were now buried in tombs within memorial burial mounds of earth with stone entrances and interior chambers. A man's weapons and shield were buried with him and a woman's spindle and weaving baton, and perhaps beads or pottery with her. At times, mounds of earth would simply be covered over piles of corpses and ashes in urns. In these mass graves, some corpses had spear holes or sword cuts, indicating death by violence. The Druid priests, the learned class of the Celts, taught the Celts to believe in reincarnation of the soul after death of one body into another body. They also threw prized possessions into lakes and rivers as sacrifices to water gods. They placed images of gods and goddesses in shrines, which were sometimes large enough to be temples.