March 2022

If he hadn’t become a geologist, Henry Gray would have been an archaeologist. He enjoys unearthing layers of history, always has, since he was a kid poring over encyclopedias and building a museum in his grandma’s attic. And if his body would work with him, he’d still be out there, digging in the dirt and climbing outcrops, making careful notes to take back to his office to plot, to describe, to study.

Instead, Gray, 99, is inside on a sunny, early-spring morning thumbing through a stack of magazines—Scientific American, Archaeology, Nature Conservancy; plotting how he’s going to pare down a heavy, 800-page book about transcendentalists—probably slice it up into sections, like he did with “War and Peace”; and musing about how he wished he would have studied more biology so he could better understand how genes can move laterally—for instance, from a sagebush plant to a human.

Gray, a celebrated Indiana stratigrapher, mapmaker, and part-time Indiana University geology professor, has taught generations of earth scientists, and continues to do so. Since retiring from the Indiana Geological and Water Survey in 1987, he’s now been volunteering his time, research, and mentorship for longer than he was paid to do it.

Henry Gray speaks to the crowd gathered for his 100th birthday.| Sara Clifford, IGWS
Henry Gray, 100, receives an honorary IU alumnus certificate at his birthday party March 23.| Sara Clifford, IGWS
Henry Gray stands with his daughter, Bonnie, in the midst of the crowd celebrating his 100th birthday.| Sara Clifford, IGWS


“There’s still lots of work to do,” he says. “I wish I could do more.”

On March 23, at a party celebrating his 100th birthday, Gray was presented a Distinguished Geologist award from Professional Geologists of Indiana, a birthday proclamation from the Indiana Senate, a Distinguished Hoosier award from the governor’s office, and honorary IU alumni status. He is already a Sagamore of the Wabash, one of the state’s highest honors, awarded upon his so-called retirement 35 years ago.

To the room full of people and praise, Gray responded by paraphrasing Sir Isaac Newton: “I do not know what I may appear to the world, but to myself I seem like a little boy on a beach, picking up the pretty pebbles and shells while the whole ocean of truth swirls around me,” he said. “And that’s exactly what I do.”

‘Following Henry’

Gray’s 1987 Bedrock Geologic Map of Indiana hangs in the hallways and in many scientists’ offices at the IGWS. That and the countless regional geologic maps Gray helped produce from 1958 to 1972 are “the foundation for all mineral, energy, water, and environmental studies by geologists throughout the state,” said Todd Thompson, state geologist and director of the IGWS.

To everyday Hoosiers, geologic studies matter because they show where to find groundwater; building materials like limestone and gravel; energy sources such as coal, oil, and gas; and minerals important to innovation like rare earth elements. “These resources are important to economic development and quality of life, and understanding the quantity and quality of these resources can be used to—hopefully—use them sustainably,” said Peter Jacobs, a professor at the University of Wisconsin-Whitewater and one of the dozen-plus earth scientists Gray has mentored.

To academics, “(Gray’s) study and publication of the distribution, stratigraphy, and history of these same resources has enabled us to construct detailed records of the environment, climate history, and chronology of these same resources, the archives of Earth history that inform scientific progress and discovery,” Jacobs said.

“Transcendent” is how IGWS geologist Henry Loope describes him, in that Gray mapped both the bedrock and surficial geology of the state. “I don’t want to say ‘unprecedented,’ but the amount of work that goes into just a quarter of that map is tremendous, and for him to do the whole state in both bedrock and surficial is really amazing.”

When Loope, a stratigrapher like Gray, joined the IGWS staff in 2013, Gray sought him out “almost immediately” and nudged him toward research topics which Gray had started but physically couldn’t finish. Henry 2—as Loope is known in their email exchanges—would drive, and Henry 1 would direct. They were still taking trips like this until shortly before the pandemic, with Gray well into his 90s, pointing things out to Loope with his cane from the side of the road.

“Being two generations removed from him, I never got to go out in the field with him in the sense of walking all around, whereas he has all the knowledge, and I’m just here to soak it up,” Loope said.

Henry Gray, 99, points out map notes to IGWS geologists Don Tripp (center) and Isaac Allred (right). Gray's Bedrock Geologic Map of Indiana hangs on the wall.| Sara Clifford, IGWS

Geologist Isaac Allred calls Gray “the father of Indiana geology … in my eyes.” Geologist Don Tripp calls him the Babe Ruth of his field and “a walking library of information.” Both have been retracing Gray’s steps on 1950s maps of Indiana so that they can collect geologic data to be inputted into a database, therefore digitizing and expanding upon information Gray and other geologists mapped nearly 70 years ago.

On a recent Monday morning, Gray huddled around a desk with Tripp, Allred, and another colleague, deciphering the abbreviations he’d made on those maps. They peppered him with questions about stratigraphic contacts and outcrops in specific quads; he answered mostly off the cuff, as if he’d just been in the field yesterday.

Geologist Jose Luis Antinao pushed back on a theory about the origin of sand in the Ohio River Formation. “Go ahead and try to prove that I’m wrong,” Gray responded, his eyes betraying a smile behind his mask.

Gray’s original maps are taped together and tearing at the well-worn creases, but staff still carry copies out into the field. Some geologic features no longer exist due to development or flooding, and could be lost to history if not for the careful records Gray and his colleagues kept.

“A lot of times, we’re just confirming work he did from decades ago and now we can present it in a digital format. And we find other things, too, but the exciting thing is, we’re following Henry,” Allred said.

In that sense, he added, “I kind of feel like an archaeologist.”

Earlier layers

Henry Hamilton Gray was born March 18, 1922, in Terre Haute. His parents were living in Jeffersonville but his grandfather was an obstetrician, so they traveled to be under his care. The young family moved often because of Gray’s father’s job—first for the Louisville Cement Co., then for the railroad, then for a machine shop—taking them to Lancaster and Zanesville, Ohio; Indianapolis; and back to Terre Haute again. As a young student, Gray never spent more than two years in any school.

He remembers no “eureka moment” when he decided to become a geologist, but counts three experiences as formative in that path.

Two involve that museum he built in his grandparents’ attic. It included collections of polished agates, fossils, and flint points which came from a summer cottage in Brown County that his grandfather had bought in 1919. He also had an outdated children’s encyclopedia set, “The Book of Knowledge,” which he read “stern to stem” learning about dinosaurs, geologic time, and climate shifts that had taken place on the very ground he was walking. He created displays and artwork for his museum and designed a geologic time clock to show the lengths of periods and epochs in hours.

When he was about 5, the family had lived in Indianapolis next door to A. B. Carr, director of the Children’s Museum of Indianapolis. Gray visited the museum often when it was in a house near where the present building is, taking mental notes on how a museum should be set up.

In 1936, when he was 14, his family took a trip to Rocky Mountain National Park. He picked up a book by the U.S. Geological Survey with a topographic map in it, and “I could read that map absolutely accurately. I could see every detail there.” Though he couldn’t understand a lot of the text yet, he took note of the USGS as a potential employer.

His parents found Terre Haute public schools to be lacking in rigor, so Gray finished the last two years of high school—which stretched into three—at a prep academy in Pennsylvania, graduating in 1940. He entered Haverford College near Philadelphia intending to major in physics on his way to getting a master’s in geology and a doctorate in mining geology.

“It didn’t work out quite that way,” he said, “only in part.”

He didn’t have the higher math skills needed for physics, and he became enamored with extracurricular activities like rock collecting in the mountains and visiting museums and historic sites. After supplementing the meager geology offerings at Haverford with classes at Bryn Mawr, he finished his bachelor’s degree in 1943, graduating with the Class of ’44.

He had hoped to land a job with the USGS in the metals or the ores and minerals branches. Instead, he was hired with the fuels branch and assigned to a field office in New Philadelphia, Ohio, where his job consisted of collecting well logs while his boss “did all the fancy work.”

He was shipped to Wyoming to work for awhile—the state where he’d met his wife-to-be, Alice, at a field camp as an undergrad. They married in 1944. But again, the boss in Wyoming had all the fun, so Gray set out to get retrained. He enrolled in a master’s program at the University of Michigan—from which Alice had earned her geology degree—and started studying stratigraphy, the description and significance of rock layers over time. He completed his master’s thesis in 1946 on the Triassic and Jurassic stratigraphy of the Camp Davis region in Wyoming, tracing the expansion of Lower Cretaceous deposits on the shelf of Wyoming to a sink line on the eastern edge of Idaho.

“I didn’t do a terribly good job with it,” he claims. “But it was fun.”

He was granted an assistantship at Penn State where he began exploring the coal mines of Pennsylvania, “strip mines, they were called then—we have to call them open pit mines now—and nobody said you couldn’t go in, so … any other fellows who wanted to go along would all go to mines where you have a high wall, 30, 40, 50 feet high and maybe as much of a half a mile exposed, and talk about beautiful impressions of coal stratigraphy,” he remembered. “That was the enlightenment to me.”

In 1948, he was hired as an assistant professor at Kent State as it was transitioning from a teacher’s college to a university. “The geology majors, taking one course after another, they found my courses plenty tough—which was true—so they created a small club called the ‘I Got an “A” from Gray Club.’”

He was still in school—working on a Ph.D. at The Ohio State University—and working summers at the Ohio geological survey when he met Charlie Wier, coal section head of the Indiana Geological Survey, at the 1952 Geological Society of America conference. He asked Wier where he could find a job in coal geology. The Indiana Geological Survey was looking for such a person.

It took nearly two years for Gray to be hired. Principal Geologist John Patton had reservations because Gray didn’t have experience with Pennsylvanian rocks in Indiana, and then-Director Charles Deiss hadn’t settled on how much the IGS was willing to pay.

It ended up being a $5,200-per-year job, initially to “spruce up” a student’s dissertation which wasn’t ready for publication. That involved a lot of fieldwork to map unconsolidated deposits along the White River. In his second year at the IGS, Gray was made map editor on top of his field duties.

Around 1958, Deiss assigned the task of coming up with a new bedrock map of the state, improving on a 1932 version. The committee decided to map glacial deposits, too, and to put them on the same map. Using Army Corps of Engineers base maps, Gray and Wier split the state into eight pieces. Then, they invited all of Indiana’s neighboring states to participate. That map series took until 1979 to finish; they mapped the Indianapolis quad twice to improve upon the data. In the ‘80s, Gray refined the statewide map to show bedrock topography and the thickness of glacial sediments. His colorful Bedrock Geologic Map of Indiana, produced with colleagues Curtis Ault and Stanley Keller, shows the types and locations of bedrock throughout the state, giving essential information to civil engineers, miners, and other professionals.

Henry Gray (second from right) laughs with former colleagues David Dilcher (left) and Dick Powell (second from left) at Gray's 100th birthday party on March 23.| Sara Clifford, IGWS

Along the way, Gray assisted Indiana counties and the soil conservation service with soil sampling, mostly for agriculture but also for determining what could be built where. He considers that work among his most important. Gray and colleague Edwin J. Hartke were honored in 1989 by the Association of American State Geologists for their report, “Geology for environmental planning in Monroe County, Indiana.” It laid out underground conditions for mineral resources and groundwater, suitability for septic systems and landfills, and hazards such as sinkholes and landslide areas in an easy-to-understand way.

That was two years after Gray retired. In fact, he’s been credited with at least 30 pieces of published research since retiring, a dozen after turning 80.

Last year over a Zoom meeting, Gray delivered pointed feedback about data Jacobs had included in a draft report. “What followed was a 10-minute lecture on the normal curve and applicable statistics,” Jacobs said. “While I teach for a living and have to stand up and talk about things on short notice, I doubt I could have delivered that lecture with the clarity he did. I further doubt I’ll be giving statistics lectures at age 99. Needless to say, I fixed the statistics.”

Back to the land

Before Alice—and Henry, "kicking and screaming"—moved to Meadowood Retirement Village 16 years ago, they lived on 10 acres on the east side of Bloomington, where he could explore the woods and pick up frogs, turtles and rocks, just like when he was a boy.

Around 1990, the Grays met with about a dozen like-minded people to establish a land trust in Monroe County. Gray served on the acquisition committee; one of the early acquisitions was the Beanblossom Bottoms preserve. Now, Sycamore Land Trust protects natural areas from development and opens them to public exploration in 26 Indiana counties.

“He’s obviously an icon in Indiana natural sciences, having literally written several of the classic books on Indiana geology,” said Christian Freitag, former SLT executive director who now leads the Conservation Law Center. Gray knew of the glacial significance of the Beanblossom Creek watershed and its unique biodiversity, and “Henry’s work to protect it stemmed from his abiding curiosity about things that make southern Indiana special,” Freitag added. “People like Henry and Dave Hudak and others set the standard in southern Indiana for connecting our science to our conservation work. Henry is a king in my mind.”

For 71 years, Alice was Henry’s exploration partner. They visited more than 200 national parks, preserves, and monuments, and she followed him into the field for as long as she was able whenever he found something he needed to inspect. He points out his favorite photo of her, walking along a trail, in “A Few Poems for Alice” published in 2013, the year she passed away. He opens to a piece he wrote, “The Presence,” about their visit to Chaco Canyon, New Mexico:

Once, exploring an ancient ruin,
I turned over a fragment of pottery,
A shard, and on the other side
Quite clearly shown were
Prints of the potter’s finger,
Whorls, neatly aligned in rows
Like scales of a fish.
The hair on the back of my neck
Rose, as I strongly felt
The presence of that person,
Separated from me by a thousand years.

After but a moment of reflection
I carefully replaced the piece
So that another, perhaps
A thousand years hence,
May make the same connection.

Gray’s fingerprints are all over Indiana geologic history. His layer in its exploration and discovery is nearly 70 years thick. His 140-plus geology publications have left a deep well of data from which scientists can draw for ages—and he’s still adding to it. He rattles off a list of three or four, maybe a half-dozen projects he’s been thinking about but hasn’t offloaded to anyone completely yet—“and I can always think of more.”

“I’m slowing down, but I think I still have all my marbles,” he said, “and I’m pretty much ready to talk with anybody about Indiana geology.”

LISTEN IN: Gray talks about his life with Alice in an interview on WTIU's Inner States.