The Racehorse landslide fossil fields

By Dave Tucker   originally posted in 2010 with occasional updates by readers.

Eocene leaf fossil at Racehorse landslide fossil fields.


August 10, 2018. These directions have been completely updated today.  It is evident from some readers comments that they have been using an incorrect route. THERE IS NO GATE on the route to the fossil fields. This route description is in part based on reports by website readers who have visited the fossil fields. If you do this trip, please send reports of current conditions and also photos of your fun day to me. DT


The Field Trip

Plentiful, easy-to-find 50-million-year-old plant fossils can be found in the Eocene Chuckanut Formation rubble left by the Racehorse Creek landslide (see that field trip here). This is a great place to take kids for the thrill of the hunt. It requires only a few minutes of walking on a boot-beaten track through fireweed of a clearcut. The landslide occurred January 7, 2009. Don’t be concerned about taking specimens- there are so many and the really spectacular ones are too large to carry. The site is on DNR property; collecting plant fossils is permitted, but it is illegal to take any vertebrate fossils from the site (almost none have been found in the Chuckanut, in any case). Such finds would be extremely important to paleontologists. If you find any animal fossils, please photograph them and email me with photos.

You can contact me at this cleverly disguised email address which only a human bean can read:  dtchico    at     gmail   dot  com.

The ‘fossil fields’ are in full sun, so take appropriate protection, and water. It can be quite hot and bright in the glare of the summer sun.

Google Earth Racehorse view

Oblique Google Earth view [2013]. Turn right beside Racehorse Creek 4.1 miles from Mosquito Lake Road. Park at 5.1 miles and walk from there.

Fossil fields map 2018

click map to enlarge. Red dash is the final footpath from the overgrown road to the fossil fields

How to get there: (Many thanks to readers who have sent updates over the years on the changing access conditions. Please report back!)

  1.       Drive WA 542 [Mount Baker Highway] east from I-5 in Bellingham 17 miles to the junction with Mosquito Lake Road.
  2.      Turn south (right). Cross the North Fork Nooksack River and turn left on North Fork Road. This paved road becomes gravel after 2.4 miles. In another half mile or so you enter lumpy  terrain along the road. When the leaves are off the trees, you may see some car-sized boulders. The hummocky topography and boulders are the deposit of an older landslide that reached the Nooksack, dwarfing the 2009 slide. The hillsides above have slid multiple times since the end of the last glacial period, and the mountain itself is called ‘Slide Mountain’.
  3.  After 4.1 miles, turn right at a major junction immediately before the bridge across Racehorse Creek (UTM E563652 N5414815). NOTE: UTM coordinates given are zone 10, NAD 27 datum to correspond with USGS topographic maps.
  4. DNR has posted that a Discover Pass is required for this logging road as it leaves the junction.Turn right on this gravel logging road, and head up the hill. In about 0.15 mile, you may note a trail head on the left marked by large rocks, with parking on the right. This side trip goes through the woods a couple of hundred yards to the rubble-choked course of Racehorse Creek. A short hike out this trail reveals effects of the January 2009 debris flows. Prior to the debris flows, Racehorse Creek was closely hemmed in with trees and brush. Vegetation is reclaiming the stream’s gravel bar, but it was swept clear by debris flows emanating from the 2009 landslide. You can walk up stream a few hundred yards to the lovely multi-tiered water fall. Believe it or not, kayakers have [intentionally] gone over the falls! But, we digress.
  5. Reach a junction at 5.1 miles (UTM E563745 N5413464) . You may note a red ’1′ painted on a tall tree on the right in a clump of woods. Park at the junction and walk up the spur to the left. [If you continue straight, you will reach a red gate in another mile. If you do so, you know you missed the right place a mile back!]
  6. The road is blocked by a pile of logs after a few hundred feet; scramble over/around this heap. Notice all the shells on the ground indicating correctly that a lot of shooting happens up here. Culverts have been removed so there are ditches to cross from here on. This road is getting overgrown as it switchbacks through a big clear-cut for the rest of the hike and is rapidly becoming a trail that you can’t loose. There is one spur to the left that’s quickly overgrowing and clearly less traveled than the correct trail. How fast do our roads get overgrown? Well, in 2010 we easily drove a big flatbed truck on this newly graded road during the ‘big bird’ fossil footprint helicopter rescue.
  7. After about a half mile of walking, watch for a trail heading left into the woods across the ditch, where the road bed makes a sharp swing to the right. (UTM E564451 N5413353). The elevation is approximately 1450′.
  8. Walk the path through juvenile forest. It’s obvious all the way to the fossils. Please consider taking pruners or a small bow saw with you to help keep this trail open. Please CUT BRANCHES next to the trunk, so sharp stubs don’t gouge other visitors.
  9. Head up or down the slope from where the trail comes into the landslide, but you won’t have to go far. The landslide is becoming overgrown, but still plenty of exposed fossil-bearing rocks. If you head straight up the hill, climbing over and under fallen trees, you will reach a ridge crest with a view over the main landslide. Fossils are abundant here.

The entire field trip is on Washington State Department of Natural Resources timber lands. Total driving time from Bellingham is less than an hour.

Racehorse landslide ferns- modern and ancient.

Youngsters I know have had no trouble negotiating the trail, boulders, logs and scree on this hike.

Note the large blocks of Chuckanut rocks along the trail, remnants of an ancient landslide that dwarfed the 2009 slide. Reach the open area of the landslide in about 100 yards, by a large, isolated Douglas fir (2011- now dead) use this tree as a landmark to find the trail back to the car. Start looking for fossils! The landslide area is grown up with lots of young trees, rocks are weathering away, but there are still fossils to see for folks who ascend to the ridge overlooking the slide, and good scenic views. Your predecessors may have left little stacks of fossils on logs for you to enjoy. You may have more success if you take the time to split the small rock slabs with a hammer and cold chisel. Head up or down the slope from where the trail comes out, but you won’t have to go far. The landslide is becoming overgrown, but still plenty of exposed fossil-bearing rocks.

Keep your fossils indoors when you get back home. These rocks tend to decompose into uninteresting little chips if they are repeatedly exposed to wet and dry conditions. Feel free to send me photos via the email address above. Please put ‘Chuckanut Fossils’ in the subject line. Perhaps I can help identify your finds; if you find something that is new to the Chuckanut fossil inventory, your photo could end up being a useful addition to science. With your permission, I’ll post selected photos on the Chuckanut Fossils page (under construction) of this website.

Visiting Korean earth science teachers hunt for fossils in 2011. The site is considerably overgrown now.

Learn more about the Chuckanut Formation, and the subtropical environment these fossil plants grew in, by going to this excerpt from a field guide by WWU paleontologist George Mustoe and colleagues.

Leaves of tree ferns (bottom left), Sassafras (center), and Taxodium (swamp cypress).


17 Responses

  1. Took a trip up to the creek last week. Had good amount of sun, had great time. WHAT a great place to find interest in geology.
    Does anyone know if the fossils at Racehorse Creek have ever been carbon dated.

    • Brad,
      The Racehorse fossils are in the Chuckanut Formation, which is known to be around 50 million years old (Eocene). The rocks can not be dated using radocarbon, as they are far too old for this method. The carbon-14 isotope can only be used for organic material less than about 62,000 years. After that amount of radioactive decay, there isn’t enough C14 left to detect. The rocks have been dated using isotopes of potassium and thorium, as well as the zircon track method.

  2. Thank you for the info. I wasn’t aware that there was that limit to testing the carbon. I think that I found some pieces of chalcedony.Could there be some around maybe replacing wood? The pieces are well rounded.
    Thank You

    • The chalcedony pebbles are more likely weathering out of the glacial till that overlies the Chuckanut in these hills, especially if the stones are more than an inch or so across. Pebbles in the Chuckanut tend to be pretty small, as the sediment was deposited a long way from source areas far to the east.

  3. Thank you. They were big and that explains the variety of rocks such as pieces of granite.
    Another question:
    I see what look like modern fauna forms. Maple,palm,fern. The climate at the time is said to have been tropic(or sub-tropic). I am wondering if this area was physically where it is now In Washington State. Was the climate tropic because it was physically near the equator?

  4. Just hit it today, easy to find. Didn’t get too far up the trail with my son (3 years old) but still came home with a pile of great fossils. Even what looks like petrified wood!

  5. Does anyone know whether the gravel road (say, from the “right turn, 5.1 miles” marker on the map and on up the hill) was laid using rock taken from the immediate hillsides or hauled in from elsewhere? The reason I ask is the abundance of well-rounded river-like rocks, including some spectacular agates, at whose origin I’d love to go rockhounding. Thanks!

    • Daniel,
      I’m going to guess that the rounded rock was hauled in from a quarry. I’m unaware of any quarries in Racehorse area. There is one down in the valley- if you go straight and cross the bridge over Racehorse Creek, you’ll eventually come to a large gravel quarry, less than 2 miles from the bridge. Stay left all junctions. I think it is an active quarry, so access may be a problem, and no guarantees it is the source of the road rock. You can go out on the Noksack gravel bars at many places and look at, and collect, all the river rock you can carry.

  6. Just got back. The road was in good condition and my small Honda made it all the way up, despite the misty rain. The trail was clear but for a few small fallen trees. The area is much more grown up now than in the pictures. I would definitely take some pruners or a large blade next time. Lots of giant chunks of shale all around. It would be worthwhile to bring a shovel and quality chisel to explore some of the large chunks that are shallowly emersed in the loose soil. There are enormous finds just laying around above the soil, I can only imagine the monster fossils that lay beneath!

  7. As of February 9, 2016:

    Gates are now open and the approach roads in good shape easily passable in any vehicle with more than an inch or two of road clearance (i.e., not suitable for your Maserati). North Fork road is potholed but mostly mud-free to the junction before the Racehorse Creek bridge; the spur leading uphill to the right is also solid, absent the potholes. 100 yds. after taking the left across from the obvious ‘1’ painted on a tree the road is thoroughly blocked–deep ditch, large boulders, felled trees. Parking for ten cars or so.

    20 minute leisurely walk up the rest of that logging road, clambering in and out of a dozen fresh trenches, no more than a week or two old. Obvious footpath to the left next to a pile of stumps and slash (described above as a “high pile of logs”); a few survey flags in yellow and blue. A machete would be handy, and probably more so in the spring.

    Thanks for the website and all the information!

  8. Visited 7-23-2016
    The hike in is exhausting. they put 17 large ditches and a road block in the road before you leave the road for the 100yd hike. Those guys must be paid per ditch. I brought by bicycle but it was no help with all the ditches. The area has gown in allot compared to these photos. Fossils are plentiful and fun fun fun to find. The view from the boulders above the dead tree landmark is worth the hike up(follow main trail past big dead tree).

  9. What a great place! We went to check it out last weekend, and the above directions were well written. The road is blocked at the last fork to the left. It’s about a 1.5 mile hike running thru a bunch of culverts, but not too bad. The thimble berries, raspberries, black raspberries, black berries, and currants along the way made it worth while. The only challenge was finding the trail at completing the 3rd switchback into the 4th on the above map. Look to the ground; someone was nice enough to put an arrow in rocks. Also look for the pink tags tied to the trees. Again thank you to the person who marked the way. The first 100 yards off the road was a little overgrown, but our machete hacked through it nicely. Head up the ridge, and you will find some really nice specimens as well as an awesome view.

  10. I live in Ellensburg and I’ve been trying to find the Chuckanut layer in the mountains are here but cannot. I went to Liberty yesterday and looked aton Blewett pass and the closed old road as well. Please advise.

  11. Took the hike to the site 09 Aug 2018…very hot about 90F with no wind (don’t recommend in hot weather) Trail was well maintained…no major issues. Took 10yr old son and 17 yr old. 10yr old loves fossils…with a little digging found lots of fossils. We did not want to take chance with kids to ridge…very steep and loose. 10yr old lost his rock hammer so if you find one up there please let me know. We had to leave because we ran low on water. We also went on hike through creek bed and found three toed fossilized footprint but rock to big to remove…took picture…keeping location secret. We hope to go again…it was alot of fun !!!! Thank you for the instructions they worked great.

  12. My 6yo daughter (Katie) and I went up last week. The directions are good. She’s very timid but was able to negotiate the ditches by holding my hand in most cases. We were able to observe a large garter snake and found plenty of fossils. We mostly took pictures of what we found but took three small fragments. One was a fern. Another was what resembled a cottonwood leaf and the final leaf was similar to a rhododendron. Katie decided to be our photographer for this expedition.

    Something that might be handy though not necessary is about 50′ feet of 0.5 inch braided rope. One section of the blazed trail after the young, dense forest was pretty steep and Katie would have had an easier time if she had a rope to pull herself up.

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