Features appear in each issue of Pennsylvania Heritage showcasing a variety of subjects from various periods and geographic locations in Pennsylvania.

Geology made Pennsylvania what it is today. The mining of anthracite and bituminous coal, the drilling for petroleum, and the production of iron and steel in the Commonwealth long drove the economy of the United States. Elucidating the history of the geological study of Pennsylvania is an integral part of comprehending its history. Henry Darwin Rogers (1808–1866), the first State Geologist of Pennsylvania, stands at the forefront of understanding the geology of Pennsylvania — a brilliant, difficult, and largely forgotten individual.

Born August 1, 1808, in Philadelphia, Rogers was the third of four sons of Patrick Kerr (1776–1828) and Hannah Blythe Rogers (?-1820). Both parents were Irish immigrants; Patrick Rogers fled Ireland in 1798 after trouble over his opposition to British rule. Young Rogers received his middle name from an individual much admired by his father, Erasmus Darwin (1731–1802), an early proponent of organic evolution and grandfather of Charles Darwin (1809–1882).

Patrick Rogers was a physician but was not financially successful. His son Henry, a sickly child, grew up in relative poverty in Philadelphia, Baltimore, Maryland, and Williamsburg, Virginia, where his father taught natural philosophy and chemistry at the College of William and Mary from 1819 until his death nine years later. Henry was educated at home by his father and, in 1825, briefly attended the College of William and Mary.

The four Rogers siblings became accomplished scientists. The oldest brother, James Blythe Rogers (1802–1852), taught chemistry at the University of Pennsylvania. The youngest, Robert Empie Rogers (1813–1884), succeeded James in that position and then went on as a noted chemist and metallurgist to become professor of medical chemistry and toxicology at Jefferson Medical College in Philadelphia. The second Rogers brother was the most famous. William Barton Rogers (1805–1882) was state geologist of Virginia and founded and served as president of the Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts. From 1878 until his death, he was president of the National Academy of Sciences, Washington, D.C.

As young men, Henry and William had a strong interest in educational methods and believed in educational reform, particularly to bring education to the “working classes.” After a brief stint in retail in 1825, the brothers opened a school at Windsor, Maryland, but it failed. A subsequent school in Baltimore also proved disastrous. Henry’s initial scientific interest was chemistry, and what science he had been taught by 1825 was chemistry. After the school ventures failed, from 1829 to 1831 he was the chair of chemistry and natural philosophy at Dickinson College in Carlisle, Cumberland County, until a dispute with the administration over his educational philosophy ended his employment. At loose ends, he tried working as a railroad engineer. He met British social reformer Robert Owen (1771–1858) that year and his interest in education was reignited. In 1832, Rogers followed Owen to London, England, to teach at one of Owen’s institutes for working men.

Rogers’s trip to England proved to be a turning point in his professional life. Continuing his studies of chemistry, he was taught by Edward Turner (1798–1837), secretary of the Geological Society of London. This opened the door to the society, where he met legendary British geologists Henry De la Beche (1796–1855), Charles Lyell (1797–1875), Roderick Murchison (1792–1871), John Phillips (1800–1874), and Adam Sedgwick (1785–1873), among others. These individuals were some of the founders of the science of geology, and Rogers became lifelong friends with them.

Rogers immediately began to study geology at the British Museum Library which, in addition to what he learned firsthand from his British geologist friends, constituted his entire geological education. De la Beche, who founded the Geological Survey of Great Britain, was a particularly close friend, and his efforts to establish a geological survey no doubt influenced Rogers’s later interest in undertaking geological surveys of New Jersey and Pennsylvania. In only one year, Rogers’s fraternity with the British geologists led to his election to membership in the Geological Society of London, the first American so honored. Before he returned to the United States in May 1833, society members entreated him to prepare reports on the geology of North America for the organization’s journal.

Philadelphia in the 1830s enjoyed prominence as a center of intellectual life in the United States, and this drew Rogers, who settled in the city upon his return. He returned as a geologist and proceeded to join and give lectures at the Franklin Institute, founded in 1824. In 1835, he was appointed chair of geology and mineralogy at the University of Pennsylvania, a position he held until 1846. He sought and rapidly secured membership in Philadelphia’s scientific associations — the Academy of Natural Sciences, the American Philosophical Society, and the newly formed Geological Society of Pennsylvania, established in 1832. Members of the Geological Society dedicated themselves to promoting a geological survey of the Commonwealth.

Rogers later became a charter member of the Association of American Geologists, which first met in Philadelphia in April 1840 with about forty attendees. In 1848, the organization evolved into the American Association for the Advancement of Science, now the world’s largest general scientific society. He served as director of the Geological Survey of New Jersey from 1835 to 1839, preparing a final report in 1840. At the same time his brother William became State Geologist of Virginia, a post in which he received much collaborative help from Henry. The mapping of Virginia — and later Pennsylvania — gave Henry an unparalleled knowledge of the local and regional geology of a substantial part of the developing United States.

The 1830s saw vital economic developments in Pennsylvania as industry expanded with the mining of coal, the manufacturing of iron, and the construction of turnpikes, canals, and railroads. Rogers resolved not to be left out of the economic largesse. In the late 1830s, he and William invested in a mulberry propagation business to supply food for silkworms for the silk industry, but lost money. In 1838, Henry opened an iron furnace for the manufacture of pig iron on Buffalo Creek, just north of Pittsburgh, but this became a financial disaster by 1843. By the early 1840s, the brothers most likely realized they were poorly suited for business and commerce.

The most significant event in Henry Rogers’s professional life during the 1830s was his appointment in 1836 as State Geologist of Pennsylvania, responsible for the inaugural Geological Survey of Pennsylvania. A bill passed by the state legislature and signed into law by Governor Joseph Ritner (1780–1869) that year created the survey. It was funded for five years with an annual appropriation of sixty-four hundred dollars, of which Rogers received two thousand dollars yearly as salary. Survey work began immediately and continued until the summer of 1842, when it was abandoned without publication of a final report because of a lapse in funding.

The survey conducted field campaigns each year from 1836 through 1842. Fieldwork proved difficult. What is now a populous and “civilized” state crisscrossed by highways was then a rugged landscape of steep ridges and river valleys, often choked with vegetation and swarming with insects. The Commonwealth’s sheer size and uneven landscape, coupled with the lack of adequate base maps, created myriad problems. In his role as state geologist, Rogers proved to be an imperious figure whose relationship with his staff was contentious and challenging at best. According to his assistants, Rogers was maddeningly disorganized and tyrannical. His disorganization led to late payment of salaries after lengthy and arduous labor. Rogers published the notes of his assistants in the annual reports of the survey, but under his own name, giving rise to claims that he did not sufficiently credit them for their contributions.

A serious and longstanding conflict developed with J. Peter Lesley (1819– 1903), who began work with the survey as a field assistant and draftsman. (He became chief geologist of the Second Geological Survey of Pennsylvania in 1874.) Lesley ardently contended Rogers never properly acknowledged his work on the initial survey. After years of bickering, in 1852 the two severed their professional and personal relationships. Fighting between them again broke out in 1857 after Lesley’s Manual of Coal and Its Topography was published by J. B. Lippincott and Company, Philadelphia, the previous year. Lesley also attempted to publish a geological map of Pennsylvania, but Rogers thwarted it. He sued Lesley, accusing him of piracy. Two years later Lesley launched his most virulent attack against Rogers, directed against the final report of the survey. The bitter feud did not end there; Lesley continued to denounce Rogers into the 1870s, a decade after his nemesis’s demise.

Rogers’s published scientific work also drew suspicion and criticism. His initial works on American geology, eagerly sought by the Geological Society of London members and published in Great Britain, were attacked by Richard Harlan (1796–1843), a well-known American zoologist and paleontologist. In 1835, Harlan accused Rogers of stealing ideas and plagiarizing the work of other American geologists. Harlan’s charges were unfounded, but his accusations were the first of several assaults on Rogers’s professional ethics that marred his career.

One of the central theoretical problems of geology during the 1830s was determining the formation of mountain ranges. One mountain range — the Appalachians — dominates much of the landscape of the eastern United States. The sprawling Appalachians extend from New England into the Deep South, over an area about 1,500 miles long from north to south and 150 miles wide from east to west. Layered rocks, or strata, in the range measure tens of thousands of feet thick. The geological surveys of Virginia and Pennsylvania gave William and Henry Rogers an unprecedented opportunity to study many details of Appalachian geology. They drew geological maps and cross sections of a large part of the mountain range that were exacting models of accuracy and detail.

Northeast to southwest-oriented folds of rock hold up ridges that characterize the Appalachian Mountains and control the topography of much of the eastern United States, especially Pennsylvania. Henry coined the term axial plane (still used by geologists) to refer to the long crests of these folds. In the Appalachians, the strata generally tilt to the southeast, the fold crests lean to the northwest, and the folds die out to the northwest, prompting the Rogers brothers to contend the force that created the mountain range came from the southeast.

During the 1830s, Henry and William formulated a theory of the mechanism that formed the Appalachian Mountains, which they first published in 1842, both in the United States and Great Britain. They explained an earthquake forced molten matter beneath the surface of the earth to move like a wave of water, and this undulatory motion caused the crust to move, fracture, and fold, forming the Appalachians. Their theory of mountain building argued for a wave-like advance of the crust toward the northwest as movement under the crust pushed it forward in one direction. Near fractures in the crust, the waves became steep and crowded, with one side bent over — similar to breaking waves approaching a shoreline. Farther from the source, the waves became lower and more widely separated.

The theory was unique in its reliance on an earthquake creating undulatory and horizontal movement to form a mountain range. However, the theory did not stop there; Henry also applied a similar mechanism to solve other cutting-edge geological problems of the day, such as the origin of coal and the phenomenon now known as glacial drift.

In the 1830s, the formation of layers of coal beds was of great interest to geologists who were particularly perplexed by the great lateral extent (in some cases, miles) of many coal beds. Rogers believed that such coal beds formed along heavily vegetated, marshy coastlines. He argued earthquakes drained sea water away from the marshes, churning their bottoms and uprooting vegetation, followed by a violent return of the sea (a tsunami in modern terms) that knocked over standing vegetation, mostly trees, and spread the dead vegetation over a large area where it rotted and was buried to become an extensive coal bed. Geologists today realize that extensive coal beds formed in vast swamps without the intervention of earthquakes, floods, or tsunamis.

Linear scratches on rocks and isolated boulders are now known to be the result of glaciers slowly pushing rocks along so that they gouged each other and, after the glacier melted, left large boulders punctuating the landscape. These processes occurred as glacial ice flowed across the landscape, particularly down valleys, but in the 1840s they were not understood. Rogers followed the lead of Charles Lyell to argue that a flood produced the striations and boulders. He posited that an undulating wave driven by an earthquake propelled an enormous flood that pushed rocks across the landscape. He also explained the impressive Niagara gorge of the New York-Ontario border, now known to be a glacial valley, as having been violently scoured by a sudden flood.

Rogers biographer Patsy A. Gerstner characterized the brothers’ theory of mountain building as “one of the most important American contributions to theoretical science before 1850.” However, Mott T. Greene, an American historian of science and geology, contends the theory was accepted by only a handful of geologists and then only for several years, so it hardly constituted a major contribution. By the 1840s, earthquakes came to be viewed by geologists as vibratory, not undulatory, and Rogers’s theory of mountain elevation was soundly rejected. Rogers never changed his mind about his theory and included a lengthy summary of it in The Geology of Pennsylvania. He became identified as a “catastrophist” by many of his colleagues, placing him outside the mainstream of geological thought, which relied heavily on more gradual processes as drivers of significant geological change.

To Rogers’s contemporaries, similar types of fossils found in disparate rock formations demonstrated age equivalence, or correlation. On the contrary, Rogers believed using fossils to determine the relative ages of rock and their correlation was risky and of secondary importance to matching the rocks by type. He simply rejected the notion that similar animals lived at the same time, the assumption of the use of fossils. He was roundly criticized throughout his career for neglecting paleontology. New York paleontologist Timothy Conrad (1803–1877) became an especially vocal critic, attacking Rogers’s work in particular for not using fossils for correlation.

After the funding for the Geological Survey of Pennsylvania lapsed in 1842, Rogers spent much time lobbying the state legislature for additional funding, especially for underwriting the cost of publishing the final report. Philadelphian William Parker Foulke (1816–1865), a lawyer and staunch promoter of science and coal field development, was a key ally. Nevertheless, resistance to further funding persisted for nearly a decade, sometimes based on nonsensical arguments. “Mr. Speaker, I shall vote against this appropriation [for the Geological Survey],” one state senator declared, “on the ground of its unfairness to other sciences of like nature with this geology. The bill, sir, makes no provision for phrenology, physiognomy, animal magnetism, and the highly important science of water-smelling; it is partial, and I will vote against it.” Lobbying for funding to complete the survey eventually proved successful and it was resumed in the 1850s.

By 1842, Rogers had alienated many in Philadelphia’s geological community. Scientific differences, exacerbated by personal animosity and jealousy arising from the survey, prompted him to search for a new home base. Rogers had delivered well-received lectures in Boston in 1843 and the city was in many respects as much an intellectual center as Philadelphia. He moved to Boston in 1845, hoping to establish a school with his brother William. From 1845 through 1851, Rogers found gainful employment as a geological consultant and by giving lectures. After the idea of a school met with no success, he tried to obtain a professorship at Harvard University. Scientific politics, in part involving old enemies in Philadelphia, stymied his attempt. In 1847, he worked closely with William to develop a polytechnical school, which became MIT in 1861.

In 1848, Rogers returned to Great Britain, where he applied his theory of mountain elevation to the Alps. The theory met with some interest, particularly from Scottish geologist Roderick Murchison, but did not gain broad acceptance and interest withered.

The General Assembly of Pennsylvania funded completion of the survey in 1851, appropriating thirty-two thousand dollars, half of which was for publication of the final report. The contract for publishing the report went to the Philadelphia printing firm of Hogan and Thompson, which spent four thousand dollars of the appropriation and went out of business in May 1852, following the death of Thompson. The contract passed to another Philadelphia printer, Parrish, Dunning, and Mears, but the company collapsed and was liquidated in April 1853. In 1855, an exasperated Rogers arranged for a publisher in Scotland.

The report, entitled The Geology of Pennsylvania, was finally printed in 1858 at a cost of $16,000 (the equivalent of nearly $400,000 today) as two volumes and a map atlas, totaling 1,631 pages with 778 engraved woodcuts, 23 full-page plates and 18 folded sheets. W. and A. K. Johnston of Edinburgh, Scotland, engraved the maps and illustrations, and the quarto volumes were copublished by William Blackwood and Sons, of Edinburgh, and J. B. Lippincott and Company, of Philadelphia.

Ever the contrarian, Rogers settled old scores in the book’s preface. He made it clear “the financial embarassments of the Commonwealth” halted funding for the survey in 1842, which forced him to work for three years on the final report “without salary, and at his own expense.” Rogers stressed he had encountered “in the performance of his duties unusual obstacles and hardships.” For example, he pointed out that the then existing topographic base map of Pennsylvania, “full of errors, was wholly unsuitable for the purpose, and it became apparent that a correct delineation of the Geology demanded a wholly new Geographical Map, or a thorough revision and correction of its most defective parts, embracing the entire mountain-chain of the state.” In concluding his preface, Rogers acknowledged the help of his assistants, noting “my grateful thanks for the personal devotion displayed by all of them, with one or two exceptions, in aiding me to the fulfillment of my duties.” Lesley surely was one of those exceptions.

The Geology of Pennsylvania was a monumental work that substantially contributed to documenting and interpreting the geology of Pennsylvania and the geological structure of the Appalachian Mountains. It devoted much discussion to structural geology and coal geology, and virtually created these subdisciplines of geology for North American students. Not only did it present much of Rogers’s research on coal, but it reviewed the known coal fields of the world. It also embodied his unique classification of Paleozoic time and the rocks of that age in Pennsylvania.

In 1807, the anatomical museum of Scottish anatomist and physician William Hunter (1718–1783) had moved from London to Glasgow University in Scotland, where it was expanded to become a natural history museum. A royal warrant was issued to create a professorship of natural history at the Hunterian Museum. The post also served as keeper (curator) of the museum. When the position became vacant on the death of the keeper, George Couper, in 1857, George Douglas Campbell, Duke of Argyll, a patron of the university, sought to fill the position. He and Rogers were old acquaintances.

In March 1854, Rogers had married Elizabeth Stillman Lincoln (?–1906). They had two daughters, Edith (1855–1862) and Mary (1860–1906). In 1855, Rogers travelled to Edinburgh, Scotland, where he lived for several months while arranging the publication of the final report of Pennsylvania’s survey. In 1857, he returned with his wife and daughter Edith to Edinburgh to stay. His appointment that year by Queen Victoria as the Regius Professor of Natural History at Glasgow University was helped not only by the Duke of Argyll but also by the influence of his important friends in the Geological Society of London, among them Murchison, Phillips, and Sedgwick. Records in Glasgow indicate that Rogers was required to present an essay in Latin to confirm his appointment. His salary was approximately 300 pounds per year. He was also made the Keeper of the Hunterian Museum in 1859.

Rogers lived and worked in Glasgow for nearly a decade, until his death in 1866. He was an impressive teacher, but according to a biographical essay by J. N. Gregory, one colleague remembered him as “personally cold, impressive and self-controlled, made few friends,” while another described him as a “quiet, modest, serious-minded man.” Rogers remained a friend of the geologists in London and became a close friend of renowned Scottish physicist William Thomson (1824–1907), later known as Lord Kelvin. He knew Charles Darwin and Darwin’s staunch supporter, the famous biologist Thomas Henry Huxley (1825–1895). They and the leading lights of British geology greatly liked and respected Rogers. However, Rogers did not join the Geological Society of Glasgow nor did he undertake any significant work on the local geology. “Rogers left no permanent impression in Glasgow or on Scottish geology,” Gregory succinctly characterized his work abroad.

“Rogers made few friends in Glasgow,” Gregory wrote. His isolation in Glasgow was due in part to the American Civil War. Local sympathies — because of commercial ties to the South — were with the Confederate States of America, but the liberally-minded Rogers sided with the North. Some Scottish peers resented the American’s professorship appointed by their queen. Rogers did little scientifically new during his last decade in Glasgow. After the publication of The Geology of Pennsylvania, he produced only about a dozen articles, mostly review papers about coal and petroleum that contributed little or no new data and novel ideas. The Hunterian Museum now has only about two dozen objects that he collected and donated, mostly Paleozoic fossils found in Pennsylvania. His greatest discovery in Scotland may have been his hiring of John Young (1805–1882), who became assistant keeper at the Hunterian Museum and greatly enhanced its collections and prestige during a career of nearly forty years.

Although only about fifty years old, Rogers’s health — mental and physical — clearly had begun failing by the time he arrived in Glasgow. His years in Scotland seem to have been marked by long episodes of despondence and dyspepsia, resulting in lengthy, recuperative sojourns in southern England and the French Riviera. The death of his daughter Edith, at the age of seven in 1862, was also a heavy blow to Rogers’s mental and emotional states.

Recovery from poor health found Rogers in the Riviera in 1865 as well as Boston to visit his brother and friends. He returned to Glasgow in April 1866 a sick man and died the following month. According to one biographer, Rogers succumbed to “overwork, a weak constitution and the effects of the Glasgow climate.”

Rogers was a hardworking, moody, and difficult genius who profoundly influenced the early study of geology. His two most substantive contributions to geology were the theory of mountain building with his brother William and his Paleozoic geological timescale. Their theory of mountain building stirred short term interest in a hotly debated and cutting-edge topic, but was soon dismissed and forgotten. The Paleozoic timescale gained no traction; apparently no other geologist adopted it. Neither contribution ever experienced a revival. Against his strident opposition to naming rock formations after geographic places, it became standard practice and continues to this day. His lack of faith in using fossils in correlation also proved to be misdirected. The rejection or abandonment of Rogers’s major geological ideas has essentially relegated him to the status of a footnote in the history of geology as a science.

What legacy Rogers bequeathed to following generations is a basic understanding of the Commonwealth’s geology embodied in the two enormous volumes of The Geology of Pennsylvania. These magnificently informative and weighty tomes — tipping the scale at nearly sixteen pounds — compiled all that was known about the geology of the Commonwealth in the mid-nineteenth century and provided a solid foundation upon which subsequent geological studies of the Keystone State have been developed. They are the scientific bequests of Henry Darwin Rogers, derided by many during his life, but securing his place in Pennsylvania’s history as its first state geologist.


For Further Reading

Gerstner, Patsy. “A Dynamic Theory of Mountain Building: Henry Darwin Rogers, 1842,” Isis, Volume 66 (1973.)

____. Henry Darwin Rogers, 1808– 1866, American Geologist. Tuscaloosa: The University of Alabama Press, 1994.

Greene, Mott T. Geology in the Nineteenth Century. Ithaca N.Y.: Cornell University Press, 1982.

Gregory, J. W. Henry Darwin Rogers. An Address to the Glasgow University Geological Society, 20th January, 1916. Glasgow, Scotland: James MacLehose and Sons, 1916.

Hoskins, Donald M. “Celebrating A Century and A Half: The Geologic Survey.” Pennsylvania Heritage, 12, 3 (Summer 1986).

“The First Geological Survey of Pennsylvania: The Discovery Years,” Pennsylvania Geology, 18 (1987.)

Rogers, Henry Darwin. The Geology of Pennsylvania: A Government Survey, With a General View of the Geology of the United States, Essays on Coal-Formation and its Fossils, and a Description of the Coal-Fields of North America and Great Britain. 2 Volumes, Philadelphia: J. B. Lippincott, 1858.

Rogers, Henry Darwin, and William Barton Rogers. “On the physical structure of the Appalachian chain, as exemplifying the laws which have regulated the elevation of great mountain chains, generally.” Reports of the First, Second, and Third Meetings of the Association of American Geologists at Philadelphia in 1840 and 1841 and at Boston in 1842, 1843.


Intervals of Geologic Time

In the 1840s, Henry Darwin Rogers objected to the use of geographic names for geological formations and also opposed applying such names to subdivisions of geological time. He instead preferred a classification of rock formations based on rock types and of geological time based on time alone. Working with his brother William, he developed a system of Latin-based names to designate intervals of geologic time. Beginning in 1844, he treated the Paleozoic (the interval of earth history from 251 to 542 million years ago) as one “geological day” divided into fourteen time intervals, which he first assigned Roman numerals and then denominated as successive stages of the day. Rock formation names were based on rock types, not on geographic place names. “The fifteen formations, or series of deposits … are called by names significant of their relative ages, the words employed suggesting metaphorically the different natural periods of the day,” Rogers asserted. He regarded this as preferable to the other nomenclatures “which rest for the most part on geographical terms, only locally correct, or on narrow and inconstant paleontological characters.” However, no other geologist agreed, and his Paleozoic timescale slipped into obscurity.


Survey Report
Meaning Geological age
(modern terms)
I Primal dawn Cambrian
II Auroral daybreak Ordovician
III Matinal morning Ordovician
IV Levant sunrise Silurian
Surgent ascending day Silurian
V Scalent high morning Silurian
VI Pre-Meridian forenoon Devonian
VII Meridian high noon Devonian
Post-Meridian afternoon Devonian
VIII Cadent waning day Devonian
Vergent descending day Devonian
IX Ponent sunset Devonian
X Vespertine evening Carboniferous
XI Umbral dusk Carboniferous
XII/XIII Seral nightfall Carboniferous




The author gratefully acknowledges and thanks Neil Clark of the Hunterian Museum; Moira Rankin and Emma Yan of the University of Glasgow Archives, Scotland; and Robert M. Sullivan and Steven E. Jasinski of The State Museum of Pennsylvania, Harrisburg, for their assistance with this article.


Spencer G. Lucas is curator of geology and paleontology at the New Mexico Museum of Natural History and Science in Albuquerque.