Andrew Wyley, an Irish geologist, was the son of Alexander Wyley who resided on the outskirts of Belfast. He was educated at the Royal Belfast Academical Institution and during 1843-1845 was the principal teaching assistant at the Clerical, Commercial and Mathematical School in Belfast. Towards the end of 1845 he joined the Geological Survey of Ireland and worked as assistant geologist under J.B. Jukes in the counties Wicklow and Wexford, in south-east Ireland. With Jukes he wrote a paper, "On the structure of the north-eastern part of the county of Wicklow", which was published in the Journal of the Geological Society of Dublin (1853-1855). On his own he contributed "On the character and mode of occurrence of the dolomite rocks of Kilkenny" to the same volume.
In July 1855 Wyley was appointed as the first geological surveyor to the government of the Cape of Good Hope, mainly as a result of the resurgence of interest in the copper deposits of Namaqualand. As part of his official duties he was asked to investigate various mineral deposits and reported on these to parliament. His first observations appeard in a Geological report upon the gold district in the neighbourhood of Smithfield (1856, 6 p), addressed to the president of the Orange Free State, in which he advised that the small amount of gold discovered there was not worth mining. His Report upon the Maitland mines (lead and copper) near Port Elizabeth (1856, 6 p), contained the recommendation that a more detailed investigation of the region be made before further mining was attempted. In his Geological report upon the coal of the Stormberg and adjoining districts (1856, 8 p) he pointed out that, as a result of the high ash content of the coal, the thinness of the seams, their frequent interruption by intrusions, and high cost of transport to the coast, the local coal would probably be more expensive than imported coal. Also in 1856 he investigated the copper mines of Namaqualand, drawing maps and sections of the mines and assessing the amounts and quality of ore available. He also collected ore samples for the South African Museum in Cape Town. The results of his observations were reported in a Provisional report upon the nature and general character of the copper districts of South Namaqualand (1856, 7 p) and in Report upon the mineral and geological structure of South Namaqualand and the adjoining mineral districts (1857, 55 p). He discussed the copper occurrences and their possible origin in some detail. In an appendix to the latter report he described the physical geography, climate, soils, vegetation, animal life, people, and means of transport in Namaqualand.
In December 1857 Wyley set out from Cape Town on a long journey through the colony, travelling first to Hopetown and continuing to Colesberg, Fauresmith, Middelburg, and Graaff-Reinet, and from there over the Suurberg Pass to Uitenhage and Port Elizabeth. His aim was to map the country geologically, draw accurate geological sections, and collect rock samples and fossils. The results were reported in Report of the Geological Surveyor upon a journey made by him, mainly during the year 1858, in two directions across the Colony, and its results (1859, 6 p ), and in a long appendix to this report, Notes of a journey in two directions across the Colony, made in the years 1857-8, with a view to determine the character and order of the various geological formations (1859, 62 p). The appendix is written in the form of a diary and contains vivid descriptions of the life and work of a field geologist at the time, notes on rural life in the colony, the places he visited, and copies of rock art. The cultural and historical information in this document was discussed by Rochlin (1960).
In his classification of the various strata Wyley mainly followed A.G. Bain*. However, he also attempted to correlate the succession of Cape rocks with that of Europe, applying the European names to the local strata. Although his use of foreign nomenclature has been criticised (e.g., Corstorphine, 1904), it helped to relate the geology of the Cape to the better known geology of Europe. During the first leg of his journey he studied the succession in the Cape Supergroup. Later he examined the same succession when passing from the Karoo to Port Elizabeth and by comparing the two sets of observations was able to correlate A.G. Bain's* Carboniferous (Zuurberg) beds in the east with Bain's Upper Silurian (Witteberg) beds in the west. He demonstrated the full succession of the Cape Supergroup and showed that it was conformably overlain by the "trap conglomerate" (Dwyka tillite) and the rest of the Karoo Supergroup. He also introduced some local stratigraphic names, for example, the Bokkeveld beds of the Cape Supergroup and the Stormberg beds of the Karoo Supergroup. His report ends with a table setting out his interpretation of the stratigraphy of the colony. The report was accompanied by an unpublished Geological map of the Cape of Good Hope... (May 1859) depicting the region south of 29?S and between 17? and 27?E, on a scale of 8 miles to the inch (1:506 880). The most important addition to Bain's earlier map was the extension of the Witteberg-Zuurberg sandstone right round the southern and south-western Karoo and northwards to the neighbourhood of the Bokkeveld Mountains between Calvinia and Vanrhynsdorp. He also produced six well drawn (but unpublished) geological sections through the colony, on the same horizontal scale as his map. The geological map is still extant; the sections were presented to the Albany Museum in 1899, but seem to have disappeared.
Wyley collected plants during his travels and gave some grass specimens to F.C. von Hochstetter*, who visited the Cape in 1857. He was thanked by W.H. Harvey* and O.W. Sonder*, in the preface to Volume 1 of the Flora Capensis (1860), "for several parcels of specimens collected chiefly along the Orange River, from Colesberg to the mouth, and in ... Namaqualand". Included were several new species. The species Venidium wyleyi was named after him by Harvey and Wahlenbergia, wyleyana and Zehneria wyleyana by Sonder. Wyley himself furthermore suggested the name Pachypodium namaquanum for the plant popularly known as 'Elephant's Trunk' or 'Halfmens'. The plant was so named and described from his specimens by Harvey in 1860. Wyley left the Cape in 1859 and in 1885 was still a member of the Royal Geological Society of Dublin.