labourers, they were usually free to find part-time work for supplemental income, and were allowed to own property (in contravention to British law at the time). Some convicts had their skills taken to use by the colonial government, as with for example the architect Francis Greenway, who designed many early public buildings. Approximately 10-15% of the convicts worked on public projects building infrastructure, while most of the rest were assigned to private employers. Land grants were abandoned in 1831 in favour of selling crown lands, which covered all land deemed "unsettled". The colonies relied heavily on imports from England for survival. The official currency of the colonies was the British pound, but the unofficial currency and most readily accepted trade good was rum. The early economy relied on barter for exchange, an issue which Lachlan Macquarie (Governor from 1810 to 1821) tried to fix first by introducing Spanish dollars, and then by establishing the Bank of New South Wales with the authority to issue financial instruments. Barter continued, however, until shipments of sterling in the late 1820s enabled a move to a monetary economy. Macquarie also played a leading role in the economic development of New South Wales by employing a planner to design the street layout of Sydney and commissioning the construction of roads, wharves, churches, and public buildings. He sent explorers out from Sydney and, in 1815, a road across the Blue Mountains was completed, opening the way for large scale farming and grazing in the lightly-wooded pastures west of the Great Dividing Range. The colonists spent a large part of the early nineteenth century building infrastructure such as railways, bridges and schools, which allowed them to get on with economic development. During this period Australian businesspeople began to prosper. For example, the partnership of Berry and Wollstonecraft made enormous profits by means of land grants, convict labour, and exporting native cedar back to England. John Macarthur, after retiring from the New South Wales Corps, went on to start the wool industry in Australia. From the 1820s squatters increasingly established unauthorised cattle and sheep runs beyond the official limits of the settled colony. In 1836, a system of annual licences authorising grazing on Crown Land was introduced in an attempt to control the pastoral industry, but booming wool prices and the high cost of land in the settled areas encouraged further squatting. By 1844 wool accounted for half