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An Introduction to Geological Maps |
Non Survey Maps
Non survey maps are listed under region and country. That is, there are maps for the whole of the
British Isles and many more of the component countries England & Wales, Scotland and Ireland.
Similarly there are maps for the whole of Europe and many more for each country: Austria, Belgium, Denmark, Germany, France Italy, Netherlands, Norway, Spain, Sweden and Switzerland.
North America and South America have recently been added along with Oceana and broader regions for Oceans and World maps.
Survey Maps
Currently our on line survey map collection features maps of the British Isles.
1 inch series - 1 inch = 1 mile
England & Wales
The Geological Survey maps of the Old Series maps were first issued in Devon in 1834-35, the rest of the
West Country in 1839-50 and for the rest of England and Wales from 1848-98. The Old Series layout and numbering system for England and Wales derived from the Ordnance Survey’s (OS) first edition topographic map which, beginning in 1805, reflected the priority of preparing for Napoleonic invasion and also a certain London-centricity.
The change from Old to New Series marked a significant change in technology. The Old Series were hand-coloured engravings of the OS topographic map with geological boundaries added. The topographic base map was generally not revised, apart from the insertion of railways, and therefore shows the landscape at a much earlier date than the geological mapping.
The national grid was introduced after World War Two. Pre-war maps without the grid have a more uncluttered and attractive appearance and often retained the hachuring, and lettering and coastline depiction of the earlier maps. The printed colours were generally lighter and less contrasting than on post war editions. Many users continued the tradition of cutting and mounting on linen to avoid wear and tear on the folds. Until the 1980s the maps were generally issued as flat maps. In 1937 there was a folded edition in a card cover incorporating geologists inspecting an outcrop.
The one inch scale was officially superseded by the 1:50,000 scale which began to be printed in 1972. Published folded maps returned in the mid 1980s with plain pale blue covers.
Scotland
The Geological Survey of Scotland adopted the first edition sheet layout and numbering system of the
Ordnance Survey for Scotland and did not vary from it; i.e. there is no Old Series or New Series as in England and Wales. The first one inch geological maps were published in 1859. The first Drift editions began in 1906 and colour printing in 1910. After 1946, the National Grid was introduced on the OS base map. Publication of the Geological Survey at the one inch scale was never completed before metrication and the intention is to complete the survey at 1:50,000 scale.
6 inch series - 6 inches = 1 mile
The six inch maps County series of the nineteenth century are all hand coloured engravings on folio
size cartridge paper sheets approximately 29 x 40 inches (72 x 100cm). They were organised on County Grids and left un mapped and uncoloured the areas outside of the county of the set. The sheets were untitled and the placename given is the most prominent on the sheet.
Quarter inch series - 1 inch = 4 miles
England & Wales
The 'quarter inch' Geological Map of England and Wales was initially published on the OS base-map the General Map of England and Wales but referred to on the geological issues as the Index Map. It was issued as hand-coloured sheets from 1889-96 and as colour prints in 1896-97 and, as revisions from 1901-05. This map series was designed to be assembled as a wall map; the blank sheets 1 and 3 were reserved for the title block and the legend, 'The Index of Colours', respectively.
Ireland
The quarter inch series was planned for 16 sheets but only 4 in the Geological Series were published - 2, 5, 11 and 16 - between 1914 and 1922. Sheet 2 was reprinted in 1935 with adjacent Scotland coloured.
Sheet 5 was reprinted for the Gov't of Northern Ireland in 1965. These unrevised sheets have a nineteenth century look inherited from the topographic plates.
Scotland
The quarter inch series was published gradually between 1904 and 1934 and was never completed. Of the 17 sheets of the topographic series, only 13 sheets were published as geological maps, issued as 12, sheets 1 and 2 were combined for Shetland. Sheets 4, 7, 8 and 11 were never published. In 1948-9, sheets 3,5,6,9,12-14 and 16 were reprinted with the National Grid as 10km squares. Subsequent reprintings were: sheet 1/2 (1969), sheet 10 (1969) and sheet 9 (1974). The early sheets have a nineteenth century look inherited from the topographic plates.
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Geological Maps
