Cornelius Cock, son of the 1820 settler William Cock (1794-1876) and his wife Elizabeth Mary Toy, farmed in the Lower Albany district of the Eastern Cape from 1856 or earlier to at least 1886. He was elected as an early member of the Literary, Scientific and Medical Society of Grahamstown (founded in 1855) on 18 March 1856. By 1859 he was a committee member of the Albany Agricultural Society, and was re-elected on the committee in July 1861.
Cock began donating fossils to the Albany Museum in 1872, when he presented a series of fossils and rock specimens from the Stormberg and Winterberg. The next year he provided the museum with a further collection, mainly illustrative of the flora of the Stormberg, as well as specimens of shale from his farm in Lower Albany containing carbon and traces of plant fossils. In 1876, "indefatigable in his pursuit of fossils amidst the rocks of Lower Albany", he presented more specimens, among them a piece of micaceous sandstone containing casts of plant stems and a brachiopod. The curator, B.J. Glanville*, named the latter Orbicula cockii and considered it potentially usefull for dating the sandstones of Lower Albany. In 1893 curator S. Schonland* named Cock as one of the six persons who had contributed most of the museum's fossil plant collection.
Cock appears to have been interestsed in other branches of natural history too, for in 1886 he presented a small Heron, Ardea sp., from Lower Albany to the museum; it was not included in E.L. Layard's* Birds of South Africa (1867).
Cornelius Cock was one of the trustees of the Kowie Harbour Improvement Company around 1884. He was appointed as justice of the peace at Peddie in 1904. He was married to Letitia Elizabeth Smith in 1849, but she died in 1860. In 1870 he married Edith Jaffrey. He had seven children.