William Maclure

History of Geology
James S. Aber

Born: 1763, Ayr, Scotland.
Died: 1840, Mexico.

Table of Contents
Abstract Introduction
Major works Later life
Historical assessment Related websites


Maclure, who is known as the "father of American geology," published the first widely available geologic map of the United States in 1809. Born in Scotland, he first came to the U.S. at age 19, but returned to London where he became a wealthy businessman. He immigrated to the U.S. again in 1796 and became fasinated with the project of making the first geologic map of the country. He travelled throughout the region east of the Mississippi River, crossing and recrossing the Appalachians many times, making geological observations. His crudely drawn map utilizes the Wernerian system of classifying rocks and shows the distribution of rocks by color. The map accompanied Observations on the geology of the United States (1809), published in the Transactions of the American Philosophical Society. Observations was revised and expanded in 1817, but without adding much new geological information and retaining the Wernerian classification.

Maclure had a rural, agricultural view of American development which caused him to oppose building of the Erie Canal. He attempted, first in Spain and later at New Harmony, Indiana, to establish an agricultural school. His efforts met with failure, and disillusioned, he eventually moved to Mexico, where he died. Besides his map and two editions of Observations, he wrote a great many other geologic works on such subjects as: West Indian, European, and Mexican geology; economic and igneous geology; and Wernerian stratigraphy.

Introduction and early life

Maclure is known as the "Father of American geology" and the "William Smith of America." These titles are based on his geological map of the United States, the first colored geological map of the country. He was born in Scotland and first came to the U.S. at age 19 to seek commercial employment. He returned to London, where he became a successful businessman. He accumulated a fortune and retired after a few years to a life of travel. He ventured widely in continental Europe and the British Isles. In 1796 he took steps to become a naturalized U.S. citizen.

Maclure received a rare color copy of Volney's geological map of the eastern United States, and he became fascinated with making a geological map of the whole country. Such a map, he thought, would be the basis for evaluating economic potential—minerals, agriculture, and transportation. Maclure undertook many journeys through the United States. He concentrated on crossing and recrossing all portions of the Appalachian Mountains.

Major works

Maclure's map was published first in 1809, accompanied by Observations on the geology of the United States in the Transactions of the American Philosophical Society. The colored map was rather crude, even by contemporary standards. Nonetheless, it was widely distributed and frequently reprinted. It became the first generally available geological map of the United States, and thus had strong influence on subsequent American geology. It is symbolic of the beginning of American geology.

Maclures's classification of strata followed Werner's scheme—see time scales. The only difference was omission of volcanic rocks in the 1809 map.

A revised map and expanded Observations were published in 1817. The only notable geologic change was in regard to the volcanic class. Basalt was conceded as volcanic, and granite also was considered volcanic in origin. The "Neptunian" rocks were, thus, reduced but not completely eliminated. Besides his maps and two editions of Observations, Maclure published several other works on West Indies, European and Mexican geology, as well as economic and igneous geology, and stratigraphy (Wernerian system).

Maclure had a rural, agricultural view of America. He failed to realize the urban and industrial potential already beginning to develop. He believed the vast interior would become a great agricultural region supporting a largely agarian society. In these views, he was not alone for the early 19th century. He thought the continental interior would be safe from warfare; whereas, the coastal region would be constantly at war with foreign powers. His prediction for the interior was correct, but the coastal region suffered only one war—the War of 1812 with Great Britain. He opposed building the Erie Canal, because of his rural outlook, yet his geological reports suggested mineral wealth (coal and salt) in western New York.

Maclure's later life

In 1819, Maclure went to Spain, where a new constitution held much promise. He intended to establish a school of agriculture; however, his educational plans failed, and the constitutional government was overthrown. He returned to the United States. In 1824 he formed a partnership with Robert Owen, a wealthy Scottish industrialist and social reformer, who had purchased the town of New Harmony in Indiana. New Harmony was a utopian community that Owen and Maclure hoped to use for the reform of education and society. They convinced several prominent intellectuals to accompany them, and they travelled from Pittsburgh down the Ohio River in the Boatload of Knowledge, arriving at New Harmony in January, 1826 (Steinmetz 2000). The social experiment lasted only two years, after which Owen returned to Scotland and Maclure journeyed to Mexico where he died a few years later.

Maclure's educational scheme was a forerunner of the later, successful federal, land-grant, college system, under which many state colleges and universities were founded. Because of Maclure's input, New Harmony became a center for geological studies in the United States during the mid-19th century. Maclure inspired David Dale Owen, son of Robert Owen, to a fruitful career in geology, and he had much influence on other contemporary and later geologists. New Harmony served as D.D. Owen's base of operation until 1860, when he died.

Left: explanation on wall outside home of David D. Owen. Right: geological laboratories. Building in center was the last one utilized by Owen; the Granary (background) was the primary site for geological collections and study. This site was a precursor for the U.S. Geological Survey.
Left: Rapp-Owen Granary was the principal building for housing geological specimens. Right: weathervane on Owen's final laboratory. It represents a fossil fish on top of two invertebrate fossils.

Historical assessment

Maclure adhered to the Wernerian system, which placed severe limits on his understanding of geology. He paid little attention to fossils, which he did not use for stratigraphy. Thus, he did not recognize the relationship between Paleozoic strata of the Appalachian Mountains and Appalachian Plateau regions. He cannot be regarded as a great stratigrapher, such as William Smith of England. Maclure was, in fact, at least a decade or more behind in terms of geological concepts in Europe. Nonetheless, his map and report were the first widely circulated account of geology in the United States. On that basis rests his claim as the "father of American geology." He also had quite progressive plans for agricultural education. In spite of much effort, however, he did not succeed in putting his ideas into practice. Nonetheless, he influenced many contemporaries and he played a significant role in development of American geology through his activities.

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© J.S. Aber (2020).