At first glance, Jim McKie wasn't sure exactly what he was seeing, but he knew it didn't belong in the juniper woodlands of Prescott National Forest.
Stepping down into the wash, the archaeologist took a closer look. Rain had cleared the sediment away, exposing two long tusks that scientists say could be 15,000 years old.Finding a mastodon isn't something they do every day.
"I knew nothing like this had ever been found on forest land before," said McKie, who was conducting a land survey with geologist Beverly Morgan.
The remains - two tusks and three teeth - were the first mastodon fossils to be unearthed in Yavapai County and only the sixth from the Pleistocene in Arizona. They're relatively common elsewhere in North America.
The first mastodons appeared in the Oligocene Epoch of the Cenozoic Era, about 38 million years ago, but paleontologist Norm Tess-man of the Sharlot Hall Museum in Prescott believes the remains found in the forest date back to the Pleistocene Epoch - making them between 12,000 and 15,000 years old.
The location is being kept secret by Forest Service officials so people won't damage or steal the fossils.
Scientists will begin excavating the site this week, hoping to unearth more of the elephant-like mammal which lived in North America at the end of the Ice Age. But for now, they are keeping both the remains and their enthusiasm under tight control.
"We do have tusks, we do have teeth, but that's all we have," McKie said. "There may or may not be more."
"It's going to be a really nice thing scientifically, but Jurassic Park it's not," said Tessman.
The Oct. 20 find, announced last week, may provide new information about mastodon life in North America.
"This is a critter that's not normally thought of as being a Western critter," Tessman said.
The animals, which were smaller than modern elephants and had long, sloping heads, fed on twigs and leaves. They stood about 9 feet tall at the shoulder with bodies stretching to lengths of 12 or 15 feet.
Their remains are more common in humid climates such as Florida and California, said Paul S. Martin, a University of Arizona geoscientist who has edited two books on the subject.
"Parts of North America are awash in mastodons," Martin said. "There are between 150 and 200 localities in Michigan, but in the dry Southwest, we haven't had many."
Although the Pleistocene is one of the better-known and most recent prehistoric periods, scientific debate still obscures the historical landscape.
The Earth was warming after the long Ice Age, drying and then cooling again. Tessman says many questions remain about the climate in which the mastodon lived and modern man was born.
Carbon-14 testing, pollen analyses and microfossils from the site soon may provide some of the answers, he said.
More than 100 sites containing the remains of mammoths - a related animal which is a direct ancestor of modern elephants - exist in Arizona. But the stockier mastodon belonged to a different species which died out completely, Tessman said.
No one yet has established what caused their sudden demise or that of contemporary mammals - including large species of horses, wolves and camels - 12,000 years ago.
Were they hunted to extinction by early man?
Martin is intrigued by the possibility, suggested by the fact the mastodons and many other large mammals "disappeared in a rush" within 2,000 years of man's appearance.
"The possibility of something going wrong in the climate has much more promise," said Martin, who has studied the topic for the past 40 years. "But we continue to work on the better bedtime story."