• Your EMAIL ADDRESS is never used for ANY purpose except to send you updates. EVER!!!!!!

    Join 1,181 other followers

  • MOUNT BAKER: Eruptive history, hazards, research.

    Visit Mount Baker Volcano Research Center websites Main website and the blog These are no longer actively maintained but are still good references [DT, April, 2020]
  • Most recent posts

  • This website first appeared December 6, 2009

    • 770,859 hits
  • Feel free to use the material on these pages.

    Creative Commons License
    This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.
    Northwest Geology Field Trips, by Dave Tucker, is licensed under a Creative Commons Attribution-Noncommercial- Share Alike 3.0 United States License. You can use what you find here, repost it with attribution to the author, "remix" it for your own purposes, but may not use it with the intent of making money off of it.

    EDUCATORS: Please feel free to use anything you find here that is useful to your mission educating people about Earth science. E-mail me if it would help to have a larger or higher-resolution version of any of the images. tuckerd at geol dot wwu dot edu

Racehorse Landslide fossil fields- access update

The trail through the clearcut leaves the road about 100 yards from where the road is now blocked off.

Since completion of logging adjacent to the Racehorse Creek fossil fields (Chuckanut Formation), the road has been blocked off about 100 yards below the trail- a tad less driving, a tad more walking. There are big berms built across the access road, but you can walk around them on the right, through the bushes. See the updated webpage here. I’ve highlighted changes in red. The big Doug fir at the end of the trail has died a slow death, smothered in the 2009 landslide debris, but it still makes for a good landmark to find the trail back out. The landslide is rapidly getting overgrown with fireweed and the like, but there are still plenty of fossils to be found. Today, I met a group of students from Harvard University geology department there, on their summer field course. All the way from Harvard to see our fossils. Imagine that. They found the place by stumbling across this website on the internet. Ain’t that somethin’?

If you go, consider taking some garden pruners to help keep the trail open. I brushed the trail today, but it can always use a little help.

Ribbed microtopography at West Beach, Lummi Island

Ribbed microtopography at West Beach. Looking south toward Village Point.

Take advantage of the fine weather and ride your bike across Lummi Island to beautiful West Beach facing Rosario Strait. There you’ll find a lovely cobble beach and fine examples of alternating sandstone and conglomerate beds in steeping dipping rocks of the Chuckanut Formation.

Take your swimsuit- or don’t!

Go to the West Beach page.

Guided field trip to Bellingham downtown geology- new date is July 9.

By Dave Tucker   June 1, 2011

Downtown Bellingham's lonely bedrock exposure

This building features igneous, sedimentary and metamorphic rocks, all within touching distance of each other. Click to enlarge.

I will lead a guided field trip to see building stones and the only surviving approachable bedrock outcrop in downtown Bellingham. The walking field trip is open to subscribers of this website, and is oriented toward people without an academic geology background. However, even a geologist may be surprised at the variety of rocks we will see. I will talk about the origins of these building stones, and the geologic stories they record.

Saturday, July 9, 2-4 PM

Cost is $30/person

On this two hour walking trip, we will see a wide variety of rocks: igneous, metamorphic and sedimentary, from many parts of North America and the world. Highlights include: fossiliferous Indiana limestone, the same rock used to face the Empire State Building; exotic stones used in sculptures; seismic hazards in Bellingham; several urbanites and how to tell them from natural stone, and much more. A printed tour guide will be provided.

The trip is limited to the first 20 paid participants. If there is sufficient interest, a second trip can be arranged. I have guided a version of this trip for WWU’s Academy for Lifelong Learning. Based on that experience, this trip will fill quickly, so do not delay.

335 million year old marine crinoid fossils, right downtown!

How to register:

Notify me of your intention to attend via email at

I will provide you with a mailing address for a check. The first 20 paid participants will be accepted onto the trip. A portion of proceeds will be donated to Mount Baker Volcano Research Center.

Alger Alp and Squires Lake geology hike-How to find the page

The location of the newly published hiking guide to Squires Lake and Alger Alp geology is here within this website.


Chuckanut syncline on State Street is covered up.

State Street syncline then. . .

The little Chuckanut Formation syncline on State Street in Bellingham is now hidden behind a wall. I hope you got a chance to see it. I first noticed this feature over a year ago and wrote about it here. It was certainly the finest example of the axis of a fold that I know of in the Chuckanut, and at a very visible scale. It wasn’t exposed to human view for much over 18 months.This is the second short-lived exposure described on this website to be destroyed or covered by construction- the other was the ‘Samish Hill slab‘, also Chuckanut Formation.

. . . and now. Sigh.

Diatryma track now on public display at WWU

The track of the extinct giant flightless bird Diatryma is now on public display at Western Washington University. The track can be found just inside the main entrance to the Environmental Studies Building. Read about the exhibit here on Northwest Geology Field Trips.

Diatryma track discoverers George Mustoe (left) and Keith Kemplin at the new display in WWU's ES building. Click to enlarge.

Racehorse Landslide fossils

A fossil tree fern and a modern sword fern from the Racehorse Creek landslide.

Here’s a place to collect 50-million-year old plant fossils from the Chuckanut Formation. The Racehorse Creek landslide, which occurred in January of 2009, has left a lot of small, fossil-bearing rock slabs in the rubble. The field trip description is here on Northwest Geology Field Trips.

Visiting Korean earth science teachers hunt for fossils.

Samish Hill slab- a curtain call.

By Dave Tucker

Saturday, July 31, 2010

Grandson Alec Foote at the site Saturday 7/31/10. Click to enlarge any image.

Construction has nearly completely destroyed the glacially smoothed and striated slab on Samish Hill in Bellingham. The site was featured in a March posting. Now there is an 8-foot-deep pit blasted into coarse facies of the Chuckanut Formation; this will be the home of the new Temple Beth El synagogue. A few interesting sites remain to be seen: coal seams, curiously-textured very coarse-grained sandstone, some coalified fossil branches. If the big yellow tracked crusher is still there, that is worth a look-see. The erratics discussed in the previous story are still there, though getting overgrown by high field grass. TH SITE FEATURED ON THIS FIELD TRIP WILL LIKELY BE GONE WITHIN DAYS, SO DO NOT DELAY. It makes for a quick outing, an hour at most on a sunny day (well, it was sunny when I started this!) this weekend.

How to find the 'Samish Slab'. Click to enlarge

Getting there: These are new directions, as access through the construction entrance is less feasable now. Begin at a foot trail on City of Bellingham right of way at the south end of 47th Street. The trail, ‘paved’ with poorly sorted glacial drift, goes south through shaded and pleasantly cool second [third?] growth forest. Turn left at a T-junction after about 200 yards. The trail ascends slightly, and shortly comes to a nexus of several trails. The construction site is visible off to the left, but instead of crossing over the ‘no trespassing’ sign, continue straight on a trail with low bushes to the left between you and the construction site. You will see one or more faint tracks going left a few feet into the grassy construction clearing. Walk east (right) along the fence at the top of the pit. If there is no work going on, you’ll figure out how to get down into the pit.

The upper part of the drill hole is in competent, fine sandstone. When it entered the poorly cemented coarser sediment, the hole sheared.

Once in the pit, examine the SE corner to see the remnant of a blasting drill hole. At the top, it is smooth and half-round, but lower down, it enters a very friable coarse granule layer and becomes very distorted due to incompetence of the lower rock layer; the drill must have crushed its way through this layer before reentering solid sandstone beneath it. Just to the left are a couple of small coal seams. Walk along the south face of the pit wall and watch for some coalified wood. At the SW corner, a cross section reveals smooth glacial till overlying the ice-planed smooth surface of the slab- an unconformity representing around 50 million years of missing time. This smooth rock surface is about all that is left of the once very extensive striated surface of the Samish Slab.

Till overlies the glacially smoothed erosional surface of Chuckanut Formation sandstone. Alec's hand is on a 50 million-year unconformity

Fay, Alec's 1-foot-long pug, for scale at the coalified wood exposure.

I climbed up onto to the big, yellow, tracked, crusher beside the big pile of crushed rock. This heap is all that is left of the rock that filled the excavation. The climb up was not simple, but the big jaws are very impressive. If you have seen a rock crusher in a geology lab, you’ll be doubly impressed at the comparison.

The tracked crusher with Alec and Fay.

Jaw crusher

Call for Chuckanut fossil photos

Readers are requested to send in photos of Chuckanut fossils for an eventual website page dedicated to them. Photos should be at least 800 x 600 pixels; identification may be attempted if you don’t know what it is, but a rogues file would be fun to look at and possibly useful for researchers. There was a major effort to identify and catalogue fossils in the WWU collection last summer, but there are probably still unknowns out there in the outcrops. Email photos with the best location info you can obtain, preferably GPS. Otherwise send along a screen shot from  Google Earth or elsewhere, with the location marked. Send to:     tuckerd@geol.wwu.edu

I’ll stick in a few photos to inspire you. The first one was sent by M. Brewer just this morning.  Thanks! DT

Racehorse Creek landslide. Click to enlarge this and all images.

The Sabalites genus lives today. This one was photographed in Florida.

Glyptostrobus dakotaensis (Heer) Brown; the only extant species lives in SE Asia in swamps.

This heavy chunk o' petrified log was packed out of Silver Creek after the Jan. 2009 flood.

General references for the Chuckanut Formation:

A succinct introduction to the Chuckanut is “Geology and paleontology of the early Tertiary Chuckanut Formation” by G. Mustoe, R. Dilhoff, and T. Dillhoff, 2007. This appears in the 2007 Cordilleran GSA Field GuideFloods, Faults, and Fire: Geological Field Trips in Washington State and Southwest British Columbia.

This Northwest Geology Field Trips website has a description of the Chuckanut Formation here.

Chuckanut fossils:

Mustoe, G., 1993, Eocene bird tracks from the Chuckanut Formation, northwest Washington: Canadian Journal of Earth Sciences, vol. 30, p. 1205-1208

Mustoe, G. E.,2002 a, Eocene bird, reptile, and mammal tracks from the Chuckanut Formation, northwest Washington: Palaios, vol. 17, p. 403-413.

Mustoe, G. E.,2002 b, Hydrangea Fossils from the Early Tertiary Chuckanut Formation, Washington Geology (on line magazine).

Mustoe, G. E.; Gannaway, W. L., 1995, Palm fossils from northwest Washington: Washington Geology, v. 23, no. 2, p. 21-26.

Mustoe, G. E.; Gannaway, W. L., 1997, Paleogeography and paleontology of the early Tertiary Chuckanut Formation, northwest Washington: Washington Geology, v. 25, no. 3, p. 3-18. GOOD PHOTOS.

Mustoe, G. E., and Girouard, S.P., Jr., 2001, A fossil trioychid turtle from the early Tertiary Chuckanut Formation of northwestern Washington: Northwest Science, vol. 75. p. 211-218 Abstract

Mustoe, G. E., and Pevear, D. R., 1983, Vertebrate fossils from the Chuckanut Formation of northwest Washington: Northwest Science, vol. 57, p. 119-124.

The Samish Slab: new expanse of striated Chuckanut in Bellingham

Ah, fortuitous bliss! Here is a field trip to a wonderful, huge slab of Chuckanut bedrock, right in Bellingham, covered with glacial striae, and nicely jointed. And a veritable petrology class of heaped salvaged erratics to boot, including bedded chert and a few pumicious lithic tuffs. But go soon, the place is slated for further excavation and destruction soon!

The 'Samish Hill' slab of Chuckanut. It measures about 200 feet across.