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Wednesday, 30 June 2004

Map Was The Start Not The Finish
CREDIT: © Cecil J. Schneer/Earth.UNH.edu
WHERE: Harmony, Indiana, USA. WHAT: first US geological map.
Thumbnail click pops-up larger image on source web site.

William Maclure's Geological Map of the USA © Uni. New Hampshire (UNH.edu/esci/)Any comparison between William Smith and William (birth name James McClure) Maclure, if based only on either's contribution to theoretical geology, will favor Smith over Maclure. On the USGS [US Geological Survey] web site, an out of print 1987 text, Explanatory Text to Accompany the Geologic Map of the United States by Philip B. King & Helen M. Beikman: Geological Survey Professional Paper 901, seems to bear out that claim, and point to reasons why:

Maps Published Before 1860

Efforts to portray on a map the geology of what is now the United States extend back more than two centuries. The first recorded attempt is a 'Mineralogic map, showing the nature of the terrains of Canada and Louisiana' (Carte min&eacure;ralogique où l'on voit la nature des terrains du Canada et de la Louisiane), by the French geologist Jean Étienne Guettard, published in 1752, at a time when a large part of the region was still French territory. Whether he visited North America is not certain, and most of his information was compiled from reports of French officers. A belt of marl and clay is shown extending from the Gulf of Mexico to Cape Breton Island, and thence inland toward Quebec. Between it and the coast is a sandy belt, and west of it a schistose and metalliferous belt. Different signs and annotations indicate the places where rocks and minerals were re-ported between the Atlantic Coast and the Rocky Mountains.

Aside from this primitive effort, the first geologic map of the United States is that published by William Maclure in 1809, of which a revised version appeared in 1817 [FIG.1]. Maclure was a Scotsman who came to America as a merchant and after his retirement became interested in the sciences; for 22 years he was president of the Philadelphia Academy of Natural Sciences. To assemble his map, he traveled widely through what was then the United States, and especially the part east of the Mississippi River. Both editions of his map were accompanied by an explanatory text, including "remarks on the effect produced on the nature and fertility of the soils by the decomposition of the different classes of rocks."

In accord with the prevailing thinking of his day, Maclure classified the rocks on Wernerian principles, dividing them into Primitive, Transition, Secondary or Floetz (including a unit of Old Red Sandstone), and Alluvial. On the map of 1817, a line is marked along the Appalachians "to the westward of which is found the greatest part of the Salt and Gypsum." In modern terms, his "Primitive Rock" corresponds to the Precambrian and other crystalline rocks of the Adirondack Mountains, New England, and the Piedmont Province; his "Transitional Rock" to the folded Paleozoic of the Appalachians; his "Secondary Rock" to the flat-lying Paleozoic farther west; his "Old Red Sandstone" to the Triassic Newark Group; and his "Alluvial Rock" to the Cretaceous and Tertiary deposits of the Coastal Plain.

No significant geologic maps of the whole United States appeared for many years after Maclure's publication, but important maps of parts of the region were made. The most notable was that by James Hall which accompanied his classic Part 4 of 'Geology of New York' (1843), dealing with the western part of the State and establishing the fundamentals of Paleozoic stratigraphy in a large part of the country. The map includes not only Hall's survey in New York but also his reconnaissance observations farther west and represents in fair detail the Northern States as far south as Virginia and as far west as the Mississippi River on a scale of 1:1,850,000. In addition, geology was also sketched on maps showing the routes of some of the exploring expeditions, such as that of Major S.H. Long's expedition to the Rocky Mountains (James, 1823), and David Dale Owen's to the northern Middle Western States (1843).

It seems that Maclure chose to follow what is now considered to be the 'wrong' classification system, and did not grasp the importance of stratigraphy, from whence came William 'Strata' Smith's nickname. Even though his work may be considered 'flawed', his observations were accurate, let down only by the theoretical model into which he tried to make them fit. His industry, application, and determination were the equal of Smith's, and his influence on later geologists was just as strong.

Maclure was much more than a geologist. Biographical [1][2][3] notes show him to be a true son of the Enlightenment, and to understand his importance to the increasingly key science of geology in the emergent United States, one needs to know a little of Maclure's involvement with Owen and his New Harmony, Indiana, utopian community. In addition to that third biographical link, Clark Kimberling has pages on the New Harmony experiment, its founder Robert Owen, and Robert's son David Dale Owen. Indiana University has a five part History of the Indiana Geological Survey that shows just how widely spread has been Maclure's influence.

In addition to the already linked monotone copy of Maclure's map, there is color [823KB file] version available on the web from Cecil J. Schneer at UNH Earth Sciences [University of New Hampshire], and even an interactive version from the David Rumsey Map Collection [check for the resources required].

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Jules Laforgue (1860-1887)
"Ah! que la vie est quotidienne."
Oh, what a day-to-day business life is.
'Complainte sur certains ennuis' (1885)