In 1873, Newton Horace Winchell made his way from Fort Snelling up the Minnesota River Valley, inspecting rock outcrops, quarries and railroad cuts. He traveled westward in direction and backward in time — eons of time.

As Minnesota’s first state geologist, Winchell’s legislative mandate was to examine every significant geological formation in the state, and explain, in essence, the very foundation of Minnesota.

And so, just 14 years after statehood, Winchell began traveling by foot, rented horse, covered wagon and birchbark canoe, collecting specimens and publishing thousands of pages of observations and conclusions about what erosion already had exposed, but also what lay beneath.

Winchell, and what he discovered over the course of more than 26 years leading the Minnesota Geological and Natural History Survey, is the subject of Chisago County author Sue Leaf’s latest book about the physical wonders of our state. A zoologist by training, Leaf has written a biography of Thomas Sadler Roberts, a physician who is considered the father of Minnesota ornithology; a memoir of her family’s canoe adventures; and a meditation on nature and Christianity — all published by the University of Minnesota Press.

In “Minnesota’s Geologist,” Leaf expertly manages the volume of geology — neither technically overwhelming nor patronizing for the lay reader. She writes with grace, reverence and awe about the task Winchell faced: His work, she wrote, would tell the story “of the immense forces of nature, of rocks and fire and ice and time — unimaginable expanses of time — that few in the young state had pondered.”

And what a fabulous laboratory Minnesota is for a geologist, Leaf notes. Virtually every rock type or change in rock type found in the U.S. exists in Minnesota, she says — from North Shore cliffs formed by massive volcanic activity 1.1 billion years ago, to southern Minnesota limestone created in ancient sea beds, to scraped bedrock, erratic boulders and thousands of lakes left by Ice Age glaciers.

Winchell was a key scientific figure not only in Minnesota but beyond its borders. Among his major contributions, Leaf writes, was his detective work involving St. Anthony Falls. Thousands of years ago, the falls was located near Fort Snelling, where the Mississippi and Minnesota rivers meet. Through Winchell’s “feat of clear-eyed reasoning and simple calculation,” he concluded that the falls’ recession meant that the last Ice Age was much more recent than experts thought at the time. Subsequent investigations would prove him right and bring him international recognition.

Though the great bulk of his work stood up to time, Leaf points out that Winchell was on the wrong side of two notable issues — failing to recognize the Black Hills’ massive gold deposits, and giving credence to the infamous Kensington Rune Stone, which purports to show Scandinavian explorers in Minnesota in 1362 and which was widely discredited by experts then and now.

Winchell’s name is not readily associated with those of other key figures in Minnesota’s early history, but his legacy lives on through his name on a BWCA lake, the U’s Earth Sciences Department and a plaque — fittingly — on a boulder by the Franklin Avenue bridge.

 Dennis J. McGrath is a former editor at the Star Tribune.

Minnesota’s Geologist: The Life of Newton Horace Winchell
By: Sue Leaf.
Publisher: University of Minnesota Press, 280 pages, $29.95.
Virtual events: 4 p.m. June 23, Bell Museum;7 p.m. June 25, Zenith Bookstore, Duluth; 7 p.m. July 6, Next Chapter Bookstore, St. Paul.