Percy G. Shepherd, son of John Shepherd, a Scottish immigrant, went to school in Colesberg. At the age of 17, just before his matriculation examination, he moved to Johannesburg to take up an appointment with the Johannesburg Board of Executors. From the end of 1888 he worked for a firm of wholesale merchants. In 1895 he started business as a commercial broker, estate agent and financial agent. His interest in geology led him to deal mainly in mining properties. Upon discovering the extension of the Witwatersrand reefs to the Middelburg district [which he described in a paper that I have not been able to identify] he floated the Middelburg Exploration Syndicate, which caused a sensation when its share price rose from an initial ?25 to ?1000. Towards the end of 1896 he prospected for diamonds around Kimberley, but without much success. Back in Johannesburg he and George Ross took options on properties on the northern Witwatersrand, in the hope that payable gold would be found north of the Main Reef, and floated companies to mine there. Some of these companies were later incorporated in North Witwatersrand Gold Mines, Ltd. Shepherd was the chairman of all the companies he floated and also owned valuable property in central Johannesburg.
Shepherd's study of the local geology was written up as The principles of geology as deduced from a study of the sedimentary formations in South Africa (London, 1897, 34p), published for private circulation only. In this work he states that his conclusions are diametrically opposed to contemporary geological opinions, but that he considers them worth publishing. During 1898 he attended some meetings of the Geological Society of South Africa and participated in the discussion of two papers dealing with the geology of the farm "Zwartkop No. 82". However, he became a member of the society only after the Anglo-boer War (1899-1902).
Shortly after the outbreak of the war, while on a visit to England, Shepherd helped to raise Lord Loch's Horse regiment. He returned to South Africa on active duty and received a medal with four clasps. After the war he became chairman of a committee of British businessmen that tried to obtain exemption from paying taxes and fees that had accumulated during the war. He was sent to London to plead their case, but to no avail. When the first municipal elections were held in Johannesburg in 1903 he originated the Reform Party and became its president. He also played an active role in opposing proposed changes to the laws governing gold mining in the Transvaal Colony. He was a member of the South African Association for the Advancement of Science from 1903 to at least 1906. Correspondence and press cuttings related to him are kept in the Strange Collection of the Johannesburg Public Library.