They passed the Billingsgate market, which was arrayed around the three sides of a large rectangular dock, or cut-out in the riverbank, where small vessels could come in from the Pool. The dock reached most of the way to Thames Street, which broadened into a plaza there, so as to shake hands with the market. Black rocks skittered out, or lodged and shattered, under the iron rims of the cart’s wheels. The horses faltered. They were pushing through a crowd of children in grimy clothes who were buzzing around gleaning those black rocks out of crevices between paving-stones.