Racehorse Landslide Fossil Fields — Wednesday, Oct. 21, 2020

Now that flowering season is over, there are new ways to make interesting plant discoveries.  One way is to look for plant fossils, which are fairly abundant in the state of Washington.  This site is very popular, in future reports I hope to report on some places I know about that are not well-known.  This site is located off a forest road near Bellingham off SR 542.  The fossils here are part of the Chuckanut Formation, a tropical world of the early Eocene, about 53 million years ago.  Detailed directions to the site can be found at the link below.  The road to the site is good, with a few easily avoided potholes; the trail to the slide area is a little over a mile.  The trail starts on a logging road, recently drivable, but now getting trail-like with alders, thimbleberries, a few hemlocks and bigleaf maples.  There is fireweed and pearly everlasting earlier in the season.  They removed the culverts when the road was decommissioned and the ditches to be crossed are somewhat annoying, but the trail is easy to the base of the slide.  The collapse that created this site was a big affair that occurred in January of 2009.   It’s amazing how quickly nature is retaking the exposed rock and debris.  Alders are the major players here.  They have nitrogen-fixing bacteria that allow them to take rapid advantage of exposed, low nutrient rubble created by landslides, forming in many places dense, almost impenetrable thickets become a dreaded obstacle for off-trail travel in our region.  Here, however, there is a trail.  Once you arrive at the base of the slide, there are a couple of downed logs where people have left pieces of rock, discards from previous visitors to the site.  The taking of plant fossils is completely legal here.  Vertebrate fossils in Washington are very rare, however, and these must be left and should be reported to the authorities.  This is the only place in the world where footprints of the ancient 7 foot tall bird Diatryma gigantea have been found.  The biggest plants fossils, huge palm leaves, are too big to remove, several can be found along the trail.  The growth of the alders has made the searching for specimens a little tougher, but there is plenty here to find, you just have to work harder.  The most open area for fossil collecting is close to top. To get there requires going straight up a steep, boot-beaten path.    A couple of switchbacks would have made a big difference.  I preferred to step off the slick trail and go up through the alders where there were leaves on the ground and trunks to hold on to.  There were some butterfly bushes up at the top (Buddleia davidii).  One was still in bloom.  They are non-native, but I think a welcome variation from the more aggressive alders.

Between us, my friend and I had two geologist’s hammers, two chisels and a sledge hammer.  Also, we had protective goggles, absolutely essential if you are going to be pounding rock.  We spent several hours splitting rocks with hammer and chisel, but the results were initially frustrating.  There were plenty of leaves, but getting a rock to crack showing a nice whole leaf was pretty challenging.  We had better results when we started sifting through the rubble.  The tools were still useful when we found pieces that were too big to haul out.  I cut off two thirds of the dross from a small section of palm leaf, leaving the fossil perfectly intact.    My friend found a pretty good fern fossil, but I found a nice conifer, maybe Metasequoia.  There were tons of leaves from broadleaf trees, but extracting whole ones was difficult.  When I have enough specimens, I may invest in a dentist’s drill to clean up some fossils; partially exposed leaves are pretty hard to identify.  The supply of material to search through is inexhaustible.  A shovel might help.  We had great fun, but were a little sore.  My thumb is swollen from the number of times I hit it with the hammer.  Each of us brought out seven or eight pieces, weighing thirty or forty pounds.  A really enjoyable day with a nice view from the top.

More Information on this Trip Report

• https://nwgeology.wordpress.com/the-fieldtrips/the-chuckanut-formation/the-racehorse-landslide-fossil-fields/