Boundaries
by Jack Nisbet

Jack Nisbet is the author of The Mapmaker's Eye, Sources of the River, Purple Flat Top, Singing Grass, Burning Sage and Visible Bones. His newest, The Collector, is due out in October.

Leafstorm
June 2008

This April, the Stonerose Center in Republic celebrated its 20th anniversary as a community interpretive and research facility. Stonerose's focus is a deposit of fossil bearing shale exposed by a roadcut just beyond the town's main street, but its reach extends far beyond the city limits. For this event, scientists from as far away as Georgia converged on Republic to visit schools, lead tours of fossil sites, sift through mystery specimens in the center's basement museum, and participate in a symposium at the county fairgrounds. Their talks, presented to an enthusiastic crowd of local fossil fans, opened up a universe of recent knowledge and clear perspective on Stonerose's place in the world.

The Stonerose fossils were created during the Eocene Period, roughly 50 million years ago, when the natural refuse of a temperate forest - mostly sticks and leaves, but also fish, insects, and bird feathers - was captured in the accumulating silt of a lake environment. Several of the symposium presenters compared the ancient lake around Republic with situations from other places and times.

Bill Rember studies leaf fossils around the Fossil Bowl racetrack near Clarkia, Idaho. This material drifted into lakes that existed about 15 million years ago around the edges of the massive basalt flows familiar today from the scabland country south of Spokane. Despite the great difference in time, many of the same plants and trees are found at both Clarkia and Republic. The fossils indicate a wet, temperate climate and mixed broad-leafed and coniferous forest similar to the American Southeast and parts of Asia. Metasequoia, for instance, is a redwood relative that today is found only in China. Fossil imprints of its needles and cones are found at Stonerose, and its last appearance in the North American fossil record comes from the much younger beds around Clarkia.

Jeff Meyers of Western Oregon University has visited several field sites in the Warner Mountains of northeast California, where fossil leaves date back around 33 million years before the present. He observes current habitats in order to find out more about the ecosystems of the past, and intrigued high school students at Curlew by getting them to think about the conditions that created fossil beds such as Stonerose. In the course of his talk, Meyers explained how small, tooth-edged leaves dominate disturbed areas while large, umbrella-shaped leaves occur more commonly in places with heavy rainfall. Then he chalked out some mathematical formulas that use these tendencies to estimate temperature and precipitation in the Stonerose world.

Rick Dillhoff of the University of Washington's Burke Museum studies Puget Sound fossil sites that are almost exactly the same age as Stonerose, but unveil a different variety of plant life. He showed examples of palm trees, mangrove pollen, and tropical cone shells taken from a site on the Chuckanut Drive south of Bellingham. The fossils there reveal a forest with about twenty kinds of conifers and over a hundred sorts of broad-leafed plants, but they don't correlate to what we know about temperature ranges for similar modern plants. Like all the speakers, Dillhoff left the audience with a series of unanswered questions about these Eocene environments.

Kathleen Pigg of Arizona State University likes to look at things very closely; she spent much of her weekend examining some of the unexplained specimens in the Stonerose basement. With a series of succinct slides she showed how easy it is to confuse maple samaras with hazelnut skirts and what that can mean for a forest. Her frequent co-author on paleontological papers, Melanie DeVore of Georgia College & University in Milledgeville, specializes in the many different manifestations of the rose family. She explained how the roses exploded into diversity during the Eocene at places like Stonerose, and why members of this family, from wild roses to hawthorns, crabapples to chokecherries, mountain ash to serviceberry, continue to flourish in the North Columbia country.

Technical advisor and long-time Stonerose board member Jan Hartford updated her progress on Stonerose Strata, a managed web site that provides access into the history, composition, placement, and recent discoveries at the site. It only takes a few mouse clicks through these strata to appreciate the mountains of fossil data that have accumulated over the past two decades, and to see how much thought has gone into the way they are being organized.

Kirk Johnson, chief curator of the Denver Museum of Nature & Science, gave two presentations. One involved the story of how, as a sixteen year old fossil nerd, he drove legendary artist and fossil fiend Wes Wahl from Seattle over the North Cascades Highway to Republic. There, at the edge of a vacant lot, Kirk kicked a stone apart to reveal an Eocene leaf imprint, an act which set in motion the events that led both to his career as a paleobotanist and the anniversary celebration at the fairgrounds.

For his second presentation, Johnson traveled across the wilds of Patagonia to a fossil site called Lake of Reeds. In dry painted hills aged just a little older than Stonerose, he found a variety of plants that look very similar to ones coming out of the roadcut in Republic. They are not, but Johnson drew several parallels between the northern and southern hemisphere during the Eocene, and together with his colleagues pointed out a whole range of similarities between their ongoing work and the reality of our modern world.

The Eocene was a very warm time on earth, with temperate forests stretching toward both the North and South poles. While it was not a particularly healthy time to be living in the tropics, the plants that lived around our latitude underwent an unprecedented burst of growth and speciation, and a surprising number of them remain with us today. Anyone who wants to understand what our present world might look like with few more degrees of annual temperature can simply visit Stonerose, sit down with a hammer and chisel, and start cracking.

What does that mean for the Stonerose Interpretive Center? According to director Catherine Brown, and just about everyone else who participated in the symposium, the time has come to think seriously about how a new facility could serve both the public and scientific aspects of their stated mission. Brown visualizes an expanded museum that could explain this large-scale story to visitors, and an updated storage and archival system to go with the Stonerose Strata website, so that paleontologists and graduate students from all over the world could come examine the place and share their insights into the past, present, and future.

Kirk Johnson, who drew the entire symposium crowd out of their chairs with pictures of a 50 million year old squashed Argentinean frog, has just published a book with Ray Troll called Cruising the Fossil Freeway: An Epoch Tale of a Scientist and an Artist on the Ultimate Paleo Road Trip (Fulcrum Press, 2008). It might be the funniest book about serious fossil study ever published, and has been successful enough that Johnson and Troll are expanding their work to include Washington, British Columbia, and Alaska. It goes without saying that Stonerose will be featured prominently in the new volume, enticing ever more people to make their pilgrimage to Republic and try to puzzle out exactly what's going on here. A new Stonerose Interpretive Center could help them do just that.

Illustration by Emily Nisbet.

Jack Nisbet Homepage