Geological History of Vernonia: A Vernonia Library Presentation

“They were millions of years old, so a few more years didn’t make much difference.”

That’s what Dave Taylor, from the Department of Geology at Portland State University, told me a few years ago when I was interviewing him about three whale vertebrae he was studying that were found in Rock Creek. In Taylor’s line of work, geologic history is measured in millions of years, not decades or centuries.

And that’s what Taylor will be talking about when he visits the Vernonia Public Library for his presentation on the Geologic History of Vernonia on Wednesday, June 8, at 6:30 pm. Taylor’s discussion will be the fourth, and final, in a series hosted by the Library and sponsored by the American Library Association’s, Libraries Transforming Communities, Small and Rural Libraries Grant.

Taylor is back again doing research around Rock Creek in what is known in geology as the Keasey Formation, a well known, 700 meter deep fossil bed, accessible in exposed areas of stream beds and road cutouts in the Nehalem River Basin. The area is famous for its abundant, distinctive, and well preserved fossils of molluscs, crustaceans, corals, marine birds, sharks, and other marine life, and aquatic and terrestrial plants.

Taylor has two partners in his current work, one of his former professors Carol Heckman, and a fellow student when he was at university, Liz Nesbit. Together they are studying an ancient methane seep deposit where animals tended to gather along Rock Creek, and are preparing to publish a paper on their findings. He says he will discuss this work as part of his Vernonia presentation.

Taylor says he will discuss the tectonic setting and the formation of the Coast Range, along with the deposits of sediment and the Columbia basalt lava flows that cap them and formed a fairly deep basin in the Vernonia area between 40 and 15 million years ago. Buried in that sediment and then exposed over time are a wealth of fossils that explain the life that inhabited the region at that time.

Taylor’s interest and enthusiasm about this subject matter can be infectious, and he works to try and make what can be a fairly technical subject interesting to the novice.

“40 million years ago the climate in this area was subtropical – there were warm waters here,” explains Taylor. “And then from 40 million to about 34 million years ago the whole earth was in a cooling trend. So that period of time when these marine sediment formations in this area were laid down culminated in an extinction event. So long-range, what I’m trying to decipher is that cooling trend in the Vernonia area and see if we can pick up any evidence of that extinction event.”

The whale vertebrae that Taylor has previously studied came from basilosaurid archaeocete, a family of extinct cetaceans – aquatic mammals that include dolphins and whales, was likely a casualty of that extinction event says Taylor. He’ll discuss a number of other animals that also died out at that same time and were preserved in the Keasey Formation, including a clam that is named after Taylor, a basking shark that is also named for him, a leatherback turtle, a pelican-like bird, and a crinoid – a long stalked, flower like species which are related to sea urchins.

A new display case at the Vernonia Library currently features some of the fossils Taylor will be discussing during his presentation.

Much of the geologic work Taylor does revolves around exploring mysteries which tend to generate even more questions, and hopefully some answers. “We don’t know everything,” says Taylor. “Most of us do things, not necessarily because they’re important, but because they’re fun and interesting.”