A topographical map of the Willow Creek anticline and nearby area shows the surface distribution of the digs various fossil sites The and nest sites mark the first maiasaur nesting ground

It has a population of only about 2,000 people, but it looks bigger because it serves a large surrounding area of ranches and farms. During the time Bob and I were waiting for the Brandvolds to get us permission to dig, we explored all that Choteau had to offer, pretty quickly. One of the spots that was of particular interest to us was a rock shop and tourist museum in town (it's now owned by the Brandvolds)

that had gems, Indian artifacts, and dinosaur fossils. There was a young woman working at the store who was pretty, shapely, and open and friendly in the way the rural Westerners tend to be. It was almost impossible not to strike up a conversation, and naturally what we started talking about was why we were in town. Her name was Amy Luthin and she was Bud Guthrie's stepdaughter. It was through Amy that we met Guthrie, and then the Peebles. And because of the meeting we ended up getting direct permission from the Peebles to dig on their land. Bud Guthrie let us set up camp on his land about a 10-minute drive along a good gravel road from the site where we were going to dig, the spot where we had dug up the first nest.

In planning for that 1979 season, we needed to make a big jump in size and organization from the previous summer. We were going from two guys in a van to a season-long, full-fledged paleontological dig. The key ingredient for such a change was money. We had to have tools and materials to prepare the fossils. We had to pay for transportation, for food for ourselves and the volunteers, and for at least a nominal salary for Bob. (I was being paid by Princeton as a preparator, so I didn't need extra money for myself.) I figured that we needed $10,000, and I set out that winter to get it. Since Princeton was not immediately forthcoming with the money, I tried a more unconventional source. I wrote to the Rainier Beer company in Seattle, Washington, explaining that Bob and I drank a lot of Rainier whenever we were in the field. (This was absolutely true then and continued to be true as the dig grew. Depending on the size of the crew at the anticline in later years, our summer supply would range from 50 to 100 cases. Bob and I made a point of putting together a beer kitty, which we kept separate from the other accounts; we did not think most of the funding agencies would consider beer an appropriate expense.) We told Rainier that if they would support the dig, we'd be happy to acknowledge them at the end of our papers, the way scientists always acknowledge the organization that provides the grant. I think Rainier must have contacted Princeton, because the chairman of the geology department (which vertebrate paleontology was a part of) informed me that the process of soliciting grant money from corporations was conducted on a university-wide basis. Free-lancing was not allowed. Shortly after this conversation, Princeton found the $10,000.

That first year at the riverbank on Bud Guthrie's land, we had 10 tents and Bob Makela's teepee. The teepee was a large affair, canvas stretched over 20-foot pine poles and the interior strewn with bits of carpet and pillows. Later I came to use one myself, and I got a small one for my son Jason, who came out to the dig each summer. We set up another one for visitors, and some volunteers brought their own. Teepees became the official domicile of the Willow Creek anticline dinosaur dig, with good reason. They're the most comfortable way to live on this land, perfected over centuries by the plains Indians. They're airy, full of light, and sturdy. You can build a fire in them, and they'll stand up to the 80-mile-an-hour winds that sometimes roar down from the Rockies and tear up tents. The teepees we used were all modeled after the original Blackfoot teepees, since the dig was in Blackfoot country. These teepees have a basic structure made of four poles leaned against each other with their tops interlocking. The four poles give the teepee its strength. On them other poles are laid on which the canvas, or in the old days buffalo hide, is stretched. The Sioux used a tripod as their basic structure, and their teepees also have a slightly different shape, not quite as tall, and with more of a slope.

The crew numbered 13 that year, including a full-time cook and Bob, both of whom had paid, official positions. Everybody else was a volunteer, which was the way we've run all the digs since, with Bob and one or perhaps two other people drawing a small salary from the grant money. (In fact, this is the only possible way to run paleontological digs, because there just isn't enough money around to pay a full crew.) Our first task that summer was to look for nests. We were fairly certain we would find at least one more. Shortly after I returned to Princeton the previous winter, I'd received a package from Amy Luthin. She'd been out to the site of the first nest during the time Bob and I were digging it up, and later in the summer she went out herself to poke around. She found something on the surface that looked interesting and mailed the pieces to me. Apart from this surface collecting, she left the site undisturbed.

In the package from Amy were fragments of eggshell and bone that looked like they might have come from hadrosaurs even smaller than the ones we had already found. This material was not from the same spot as the first nest, but the location was on the same level of the anticline as the first nest. A concentration of bone and eggshell like that suggested to me a second nest. But when we set out in July 1979 to uncover what Amy had found, we couldn't discern the outline of a nest; we couldn't tell where to dig and where not to dig. So we didn't dig at all. We collected from the surface and let the site weather for a year. This is a fairly common practice. Wind and rain are not only inexpensive; in the short term, they have a more delicate touch than a paleontologist's ice pick. (And when I say we let the site weather, that doesn't mean we sat around and waited. We went on to prospect for other nests, to find them, to dig them up, and to dig up a variety of other fossils. We always had several bone deposits that we were excavating at any one time at the Willow Creek anticline.) The next year, we again collected from the surface and again we swept the loose dirt and screened it for bones. Again we decided to let it weather. Not until 1981 did we actually start to dig into the mudstone. Then we found that the reason it had been hard to see the extent of the nest was that the nest was not complete. What remained was only a portion of the bowl-like shape we had seen in the first nest. But that portion did contain the badly weathered bones of seven extremely young dinosaurs and one embryo.

Amy Luthin's nest, and even in 1979 we thought it would turn out to be a nest, was significant because it was the first hint that

The shortgrass prairie and eroded badlands of the Willow Creek anticline; to the west, the Rocky Mountains rise in the background. Camp (right) was a collection of teepees, tents and trailers.

In the characteristic paleontological stoop, crew members search the chipped rock of Egg Mountain for fragments of eggshell and bone.

Maiasaura Skull

The Good Mother Lizard. Top: The reconstructed skull of the original specimen of Maiasaura peeble-sorum, found by Laurie Trexler and prepared by Pat Leiggi. Above: The jaw of a nestiing maiasaur, two and a half inches in length. Right: An ice pick is one of the standard tools, used to chip away dirt and fossil bone; here, work is done on a piece of legbone still embedded in the ground.

The paleontologist (right), contemplating his fossils; in front of him lies a thighbone from the Brandvold site that has been cast in a plaster jacket and pulled from the ground. Below: Barbara Haulenbeek packs another jacketed bone from the same site back to camp. In the winter, the protective jackets will be removed so that the bones can be carefully cleaned, studied and, if necessary, reconstructed.

Small treasures. Fragments of bone (left) from a nest of hatchling maiasaurs look like so many dull bits of rock. The cross section of a hypsi-lophodontid egg (below) shows the hints of bone that signal the presence of a fossilized embryo. Egg Island yielded 19 eggs containing such fossils, the first preserved embryonic dinosaurs ever found.

A reconstructed clutch of hypsiloph-odontid eggs from Egg Mountain (above), laid by the mother dinosaur with their ends embedded in soil; these eggs, preserved whole, never hatched. Right: An egg of an unidentified variety of dinosaur, also from Egg Mountain, and Matt Smith's model (based on a CAT scan) of an embryonic hypsilophodontid reaching hatching age.

After a failed attempt to lift a jacketed maiasaur nest out of Egg Gulch by helicopter, Bob Makela, Lisa Ulberg and Robin Voges cut the nest in two. The second try was successful.

Jack Horner walks over the Camposaur pit, one part of the big bone bed that contained the fossil remnants of a herd of 10,000 maiasaurs.

Marion Brandvold's find was not an isolated oneā€”that more than one dinosaur might have come to this upland plain to lay her eggs. Amy's find was also intriguing because it was on the other side of the scooped-out center of the anticline from the first nest. And even though the middle of the anticline was missing, we could tell that the rock in which both these nests were located was the same rock. They were both on the same bottom layer of the anticline, on what is called a single fossil horizon. The layer was of mudstone laid down by stream flooding. And, having the signs of two nests in that layer, it behooved us to look for more. We did that by following the mudstone layer all over the anticline, on our hands and knees.

Up and down the anticline we went, day after day, seven or eight people, some of us wearing rug-layer's knee pads, crawling on sharp rocks and pebbles in the sun, grousing and moaning about either the rocks or the knee pads themselves, squinting at the ground two or three feet away to try to distinguish in the glare of the sun a half-inch bit of dusty black rock that might be a fossil bone from the other half-inch bits of dusty gray, brown, red, green and white rock.

The normal way to look for dinosaur fossils is just to walk along and look at the ground. In the Judith River formation, which preserves swampy, lowland terrain, you step on fossils all the time, and you can see them when you're standing up. In the preserved dry uplands (dry then and dry now) of the Two Medicine formation, on the scruffy slopes of the Willow Creek anticline, there is no such luck. You could walk the terrain for a year and not see anything. You have to keep your nose somewhere between a foot and 18 inches away from the ground in order to have a chance of finding anything. In fact, because of the difficulty of work at the Willow Creek anticline, I tried to get volunteers who had not been spoiled by other, easier dinosaur digs. After two or three days or a week of crawling and not finding anything good, experienced paleontological volunteers might well have packed their bags and left, discouraged and dispirited. Newcomers didn't know any better. Once the newspaper and magazine articles and the television reports about our finds started to appear, right after we found the first nest in 1978, I began to get letters from people who wanted to volunteer. There were also people at Princeton who wanted to help, as well as people whom Bob and I knew in Montana. For unknown volunteers, I usually waited until they had not only written two or three times, but had also called me on the telephone. At that point I would explain how difficult it was, that there wasn't even a latrine (we just carried a shovel over a hill), and that the routine was six days of work and one day in town to buy food and wash up. After all this, if the people I was doing my best to discourage were still interested, I gave them directions and told them to bring a tent or a teepee.

My guess, and I was usually right, was that the ones who were persistent enough to get me to accept them would be persistent enough to get through the hard work and the discomfort to experience the rewards. The heat and the bruised knees faded in importance as soon as we found something. Some days, of course, were better than others. The entries in my field journal for July 1, 1979, show that we found the remains of three nests in that one day. On July 1, our knees didn't hurt at all.

For each of the nests we found that day, the signal that we had something was a concentration of crushed eggshell on the surface. Once we had found an eggshell concentration, we got down on our hands and knees with ice picks, whisk brooms and dustpans. We carefully removed fossils and dirt, digging down to look for the telltale bowl-shaped boundary between green and red mudstone that marked a nest. We screened the dirt we took from each site for fossils, mapped each nest on a grid and made a map of all the nest sites. The concentrations of eggshell did not always turn out to mark a nest; sometimes we would dig down and find no bowl-shaped boundary, no outline of a nest. Eggshell on the surface was not always a reliable indicator of a nest because the Willow Creek anticline was unlike most

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