A month later, the legislature gave the Commissioners "exclusive power to lay out streets, roads, and public squares, of such width, extent, and direction, as to them shall seem most conducive to public good, and to shut up, or direct to be shut up, any streets or parts thereof which have been heretofore laid out ... not accepted by the Common Council." The jurisdiction of the Commission was all of Manhattan north of Houston Street, and into the Hudson and East Rivers 600 feet beyond the low water mark. They were given 4 years to have the island surveyed, and then to produce a map showing the placement of future streets. There were few specifications given to them about those streets, except that streets were to be at least wide, while "leading streets" and "great avenues" were to be at least wide.