Geology at home

For this month, my book group chose a novel by Tracy Chevalier called Remarkable Creatures, about 2 British women who made important fossil finds in the cliffs outside their seaside village in the 1800s.  I am enjoying it so far–and it got me thinking about the fossils I had found right here at home a while back. 

New homes were being built in the woods behind us, and a deep trench was dug for the water and sewer lines.  Six to eight feet down, layers of orange, pale green, and yellow ochre clay rocks were visible.  The heavy machinery spewed these rocks out of the trench–and they were filled with fossils. It was fascinating.  The rocks were easy to split into layers, and in the layers were impressions of clams, tube worms, and snails.   It seems that our woodsy, hilly home had once been under the sea . . . 

I did some research.  Way back in the Eocene Era, from 34 to 56 million years ago, the Southern Willamette Valley was indeed under water.  It was part of a deep bay with the inlet in the north, (Portland would have been a deep-sea port) and it lasted for 25 million years.  The layers of sediment that formed on the bottom are over a mile thick.

The climate was warm then.  Volcanos were actively erupting and the Western Cascades were formed–the eroded remnants of which form the Coburg Hills today, as well as the cliffs above the McKenzie Bridge and Opal Creek areas.  These areas formed the shores of the vast bay.  As time went on, the seabed rose, and the bay drained. 

The site of my home became part of a vast, quiet, swampy, grassy valley.  It was roamed by elephants, giant bison, and ground sloths.  Rivers carved it, ice ages shaped it.  As the climate warmed once more, flooding from Ice Age melting made the Willamette Valley into a lake 100 miles long, 60 miles wide, and 300 feet deep.  This lake left left about 15 feet of layered, sticky sediment. 

I learned all of this information from a beautifully illustrated, fascinating book called In Search of Ancient Oregon, by Ellen Morris Bishop.  I checked it out of the library and highly recommend it. 

I wonder which era my fossils are from–that truly ancient seabed of the Eocene era, or the more recent Pleistocene lake. I suspect the latter is more likely:  that my hilly neighborhood was along the edge of the huge lake, and that my fossils were the creatures that lived in the muddy, marshy shores: freshwater clams and snails.  It boggles my mind to imagine the span of time, and to try to visualize all the changes my little plot of yard has undergone throughout the ages.

About reinkat

I am an iconographer, and have been studying Russian/Greek icons since 1995. I'm married with 3 children. I love hiking, camping, animals, my family and church--and icons.
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8 Responses to Geology at home

  1. ritaroberts says:

    I love your blog about fossils as one of my hobbies is collecting them. You might like to check out the story of Mary Anning who became the greates fossilist the world ever knew. She was born in Lyme Regis England a famous fossil area.

    • reinkat says:

      thank you for your response. I don’t know a lot about fossils but am very interested in them, and the way that rocks tell the story of the past. The novel I mentioned at the front of the post, the one that got me thinking about my own little fossil collection, is a historical fiction story about Mary Anning, and Elizabeth Philpott. I think you would like it. The discoveries Ms. Anning made are astounding. Have you been to Lyme Regis to collect specimens?

  2. ritaroberts says:

    Im glad it was Mary Anning you were talking about,and yes I went to Lyme Regis many years ago.Fantastic place as well as for collecting fossils. My favourites are Brachiopods and Trilobites, and of course the famouse Amonites. Fossil collecting is a facinating and healthy hobby because it gets you out visiting some beautiful places adding to the excitement of finding the fossils yourself. That is if you have the time as I see you have a responsible job.

  3. reinkat says:

    My fossil collection is limited to my backyard specimens of clams & snails in fragile claystone, a few coastal snails and clams that are solid rock, and a few pieces of petrified wood from the southwest U.S. I haven’t ever gone out specifically to collect. Most places that are known to have fossils are off-limits. We have hiked in areas like that. I love to just walk, see, enjoy–and abide by the no-collecting rules!
    I used to be an illustrator of children’s materials, and for a while was almost “typecast” as a dinosaur artist. I studied them a lot, and they are fascinating. It was disappointing to me to find out that Oregon never had a true dinosaur–it was under the sea at the time.
    Lyme Regis sounds fascinating. Such a rich source of fossils–I got the impression that they were scattered everywhere. Are people allowed to just look around and take what they like, or is protected now as our fossil areas are in the northwest U.S.?

    • ritaroberts says:

      Thanks for your information about dinosaur’s Im not very well up on those but the kids love them. Yes Lyme Regis is a fascinating area for fossil collecting and as far as I know you are allowed to collect whatever you find. However I think you have to be under supervision now. When I went there many years ago anyone could collect whatever they found. There is another place not far from Lyme Regis called Lullworth Cove where I found a beautiful Amonite. I like your Iconography by the way, and I love the Icons they have here in Crete. Stay in touch.

      • reinkat says:

        I’ve been reading a geology book about ancient Oregon, my source for much of the original post. It is giving me the urge to go out and look at rocks, and search for fossils. I would love to head out to a dry creekbed (if there is a dry one this year) in Eastern Oregon and search for fossils. The east side was not under the sea so who knows what might turn up! Evidently there are many many plant fossils, and a lesser amount of early horses, camels, rhinos and all sorts of other strange beasts.
        Dinosaurs are totally cool. I have come to think that they didn’t actually go entirely extinct–but some of the smaller survivors evolved gradually into birds.
        Thanks for the kind words about my icons. I love icons from Crete, they are extremely beautiful.
        How large is the ammonite you found in Lullworth Cove? I know some of them are very impressively-sized specimens. Did you have it polished? The colors are amazingly beautiful, although leaving it natural makes it seem so much more real.
        I would have loved to see Elizabeth Philpott’s collection of fish. There must have been some amazing ones.

  4. rita roberts says:

    Hello,Answer to your question about the amonite I found at Lullworth Cove,well it was’nt all that big but never the less I was thrilled at finding it and I know there are some huge ones.I must go back some day. I do prefer them in their natural rough state as found, However when polished it does bring out the colours.

  5. reinkat says:

    Hello Rita,
    I love to see the fossils in their natural state, too. It makes them more real, less like a piece of jewelry or art. I am angling for a chance to float down the canyons of the John Day River, right through the fossil beds. I have about a 50/50 chance of getting to go. It will be a totally wonderful experience. I hope you are able to return to Lullworth Cove. Do you find many artifacts on Crete? Are there fossils there as well, in the limestones that it seems must abound in that area?

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