The Willamette Valley during the Ice Age

Although no glaciers got into the Willamette Valley during the ice ages between 2 million years ago and about 12,000 years ago the effects of this cold interval were profound on this area. Glacial ice is probably the most effective agent to wear and grind down rock ever devised by nature.

The ice ages saw incredible amounts of material being flushed into the valley from the east out of the Cascades. As this great mass of sand, silt and gravel flowed into the valley born on streams it began to clog and plug the natural stream system creating a network of shallow ponds, lakes and wetlands. Along with this changed physiography came a lush vegetation that would support a rich assemblage of mammals from mice to elephants.

In the past 100 years any deep excavation or similar construction in the Willamette Valley would often turn up the bones of mammoth, mastodon and prehistoric bison. Dr. Thomas Condon began a collection of these large mammals and later Dr. Earl Packard similarly collected and published on this ice age fauna. The latter paleontologist began to construct the rudiments of a mammalian food chain from smaller organisms as beaver and other rodents up to predators as wolves, fox, bears and cats.

In the 1980s William Orr, director of the Condon museum of paleontology in Eugene added to the collection with the remains of muskrat and several more bones of bison, elephants and ground sloths.

During the mid 1990s archaeologists began a series of excavations in the Woodburn area in an attempt to find human cultural material associated with the large mammalian remains. Under the direction of Dr. Alison Stenger those efforts were richly rewarded in a series of archaeological digs conducted over several summers into the millennium.

In 2002, several thousand bones have been extracted from the Woodburn bog sites as well as fossil bird shell and bone, insects, amphibians and a wealth of vegetable material including leaves wood and fossil pollen. The center piece of their labor however is several strands of human hair that date back to between 11,000 and 12,000 years into the past.

Now, at last, a complete picture of the Willamette Valley Pleistocene or “ice age” environments is emerging. The localities and fossils have attracted international attention and a team of paleontologists and archaeologists are engaged in unraveling this most interesting chapter of Oregon pre-history.

Written by Dr. William Norton Orr, July, 2002

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Bibliography:

Excerpts from Dr. Orr’s presentation on prehistoric animals in the Willamette Valley, June 2002, at the Salem Public Library with his permission, and from excavation work at the Woodburn bog mentioned in the article above.

This article originally appeared on the original Salem Online History site and has not been updated since 2006.