2022-07-08 Walk to the Rocks Field Trip

Walk to the Rocks:  Geology of Tamanowas  Rock and Peregrine’s Rock, Chimacum, WA

The Trip—Lead by the QGS Rockstars

Tamanowas  Rock

On Friday, July 8, 2022, the QGS Rockstars (four of our geologists) will lead a 4-mile, 4-hour hike (11AM—3PM) from HJ Carroll County Park near Chimacum to the Tamanowas Rock Sanctuary, then up on top of Tamanowas Ridge to see Peregrine’s Rock.

The hike can be vigorous, steep, and rough in parts and is tailored to agile citizen scientists who are already knowledgeable about geologic principles and vocabulary. Subjects to be discussed include the glacial history of the Quimper Peninsula, specifically Chimacum Valley, glacial erratics on the Peninsula, and the geology of the underlying Eocene volcanic rocks. Tamanowas Rock is a special part of this story and a sacred place of the S’Kallum people.  Tamanowas Rock is the remnant of an explosive volcano that erupted about 43 million years ago.  It is comprised of Adakite, an unusual type of lava that forms under anomalously high temperatures when a subducted oceanic plate starts to melt.

Peregrine’s Rock, man for scale

Conversely, Peregrine is a glacial erratic named by Erik Nagel, a participant in our Great Erratic Challenge two years ago. It currently is the largest erratic documented on the Quimper Peninsula. The Rockstars are currently preparing a concise, illustrated guidebook (pdf), which will be emailed to all attendees in early July.  The field trip is limited to 50 hikers and requires advance registration (by snail mail) and a $15 fee (by check).  Deadline for RECEIPT of your form and check is Friday, July 1.  Those who register but exceed our limit may request to be placed on a wait list. The trip will run no matter the weather conditions, since the Rockstars will have travelled long and far to lead this trip.  Click on the the registration button below to download the required form.



2021 Geology of bluff along North Beach, Fort Worden


Guide to the Geology of the Bluff along North Beach, Fort Worden

Have you ever looked up at the bluffs while walking along the beach at Fort Worden and wondered how the layers formed?  If so, you’ll want to use this self-guided tour of the North Beach bluff from Fort Worden to North Beach parking lot to learn about what you see.

This long-version of our recent guides describe the geology along a one mile stretch of the north shore, extending westward from Point Wilson at Fort Worden State Park. The walk is less than a mile one way.

The geologic interpretations will provide you with a concise understanding of these beautiful Pleistocene glacial deposits… Have fun and save your questions for the next Quimper Geological Society talks.

2021 Summer Geology Beach Guides–North Beach, Port Williams, & Nodule Point

2021 Summer—Three Geology Beach Walks and Detailed Guides

We led three different beach walks where you can learn more about the geology and sediments that form the bluffs and supply the beaches. Each trip ran twice.  Because of parking and logistical difficulties, attendance was limited to about 20 participants for each trip. Field trip guides are available for downloading.  This are preliminary and dynamic; we may update them as more information becomes available.


  • Where: Meet at Fort Worden in the parking pad south of Battery Kinzie for a two-hour walk. State parks pass required to park here.
  • What: On the one-mile walk west towards North Beach county park, we’ll see a wide variety of glacial deposits including outwash and marine sediments, a peat layer, a “buried” forest, and glacial erratics on the beach. All are well exposed in a steep bluff at sea level. Generally, we walk up section (through younger deposits to the west). There are various return routes.
  • Leader: Kitty Reed, retired geologist, and several assistants.
  • For: Persons with limited geology background, easy walking across some bouldery section of beach.
  • To download the guide, click this link.


  • Where: Meet at Port Williams, NE of Sequim for a two-hour walk. Carpooling recommended; small parking lot at this county park.
  • What: We’ll see glacial deposits, including Vashon till and Possession drift, various outwash deposits, and locally derived alluvium of the Dungeness River. All are well exposed in a steep bluff at sea level.
  • Leader: Kitty Reed, retired geologist, and several assistants.
  • For: Persons with geology background. This is the least known of the three areas we’ll visit this summer. We invite active discussion. Generally easy walking
  • To download the guide, click this link (not yet active 9/12/2021).


  • Where: Meet at the East County Beach Park,  NE of Nordland on Marrowstone Island for a four-hour walk. Carpooling strongly recommended for this small (8-10 car) parking lot.
  • What: On the four-mile walk to the Point and back, we’ll see Vashon glacial till, outwash deposits, and glacial erratics. All well exposed in a steep bluff at sea level and on the beach. At the point, well see sandstone of Scow Bay, a basalt dike that intruded the sandstone, and many cemented sandstone concretions (not nodules, despite the point’s name). They are worth the long walk.
  • Leader: Michael, retired geologist, and several geohelpers.
  • For: Persons with limited geology background. This is the only walk that encounters bedrock of the three areas we’ll visit this summer.  Moderate walking across some bouldery beach, your shows will get wet.
  • To download the guide, click this link