Martin Smith found the first fossil mammal in South Africa, probably in 1838 or early in 1839. It consisted of part of a skull, with horn cores attached, superficially resembling the remains of an ox. Smith found the fossil about twelve meters below the surface in a deep alluvial deposit on the banks of the Modder River near Thaba Nchu in the Free State. The find was shown to Andrew G. Bain*, who made a drawing and wrote a brief description. He estimated that the horns, measured along their curve, must originally have had a span of over four meters in the living animal. On 21 February 1839 Bain sent his information to Dr Andrew Smith* in England, with a request that the find be made known to the Geological Society of London. Bain's letter was read before the society on 20 November 1839 by Charles Darwin* and recorded in its Proceedings (1838-1842, Vol.3, p. 152) as follows (Lister, 1949, p. 230 Note 21): "An extract from a letter addressed to Dr. Andrew Smith by A.G. Bain, dated Graham's Town, Cape of Good Hope, Feb. 21st, 1839, and communicated by Charles Darwin, Esq, was first read. The object of this extract is to announce the discovery by Mr. Martin Smith of the piths and portions of the head of an ox in the alluvial banks of the Modder River, one of the tributaries of the Orange River, and 40 feet below the surface of the ground."
The fossil was later described and named by H.G. Seeley* in a paper entitled "On Bubalus bainii (Seeley)" in the Geological Magazine (1891). It has since been renamed Pelorovis bainii and is in the South African Museum. Nothing is known about the discoverer.