James Netherton Cock, son of William Frederick Cock Jr and his wive Lucy Ann Cock, was an acting tide-waiter in the employ of the Cape civil service during the latter half of 1876, and clerk to the civil engineer at Port Alfred during the first half of 1877. In February 1879 he was appointed as inspector of the native location at Bathurst, a post he occupied until he retired on pension in 1905 or 1906. However, he seems to have resided in Port Alfred during most of these years. Upon his retirement he was appointed field cornet at Bathurst.
In 1895 Cock donated ethnological specimens to the Albany Museum, including a complete pot from a midden near Port Alfred. This find caused the museum's curator, S. Schonland* to send his assistant, F.A.O. Pym*, to further investigate the middens near the town. In 1898 Cock and Pym recovered pottery fragments from one of these middens for the museum, while Cock also presented 20 stone implements from the same place. The midden also yielded portions of human skulls and the lower jaw of the vlakvark, Phacochoerus aethiopicus, which was then not known to have occurred in the southern Cape in earlier times. All the pottery which they recovered was described by Schonland in the Records of the Albany Museum (Vol. 1, pp. 25-) in 1903. Years later, in 1907, Cock donated fossils from Bathurts to the museum.
Cock married Florence Elizabeth Margaret, born Keen, in 1878. After her death in 1885 he married the widow Annie Caroline Botha in 1887. He had six children.