I hiked the Mount Pilchuck trail a week ago and just published a field guide on the Northwest Geology Field Trip website and you’ll find it here. I was motivated by an email from long-time reader Wendy B. She hiked Pilchuck last fall and asked me about this ‘standing stone’ near the summit.
Wendy asked: “One quandary that mesmerizes hikers and is the subject of much debate is the two-story tall “shark fin” rock about ten minutes from the lookout. Curious minds want to know how it came to have this shape and rest in this striking position”
So I finally hiked Pilchuck to see if I could deduce an answer for Wendy. I think I did, its in hike description. Also of geologic interest is the rock itself, the fine-grained granite of the Pilchuck Stock and its sets of parallel joints. The hike is famous for its fabulous views from the summit lookout, as well as the atrocious road to the parking lot.
The summit block of Mount Pilchuck. The lookout is on the left high point. The trail ascends through really well exposed granite of the Pilchuck Stock. What’s a ‘stock’ you might ask? Go here to find out.
Filed under: geology, Geology field trips, igneous rocks, North Cascades geology, Washington Geology | Tagged: Geology field trips, geology hikes, granite, joints in granite, Mount Pilchuck |
Northwest Geology Field Trips 
Thank you Dave and Scott for making this trek and sharing your expertise! Very interesting to learn more and gain more appreciation for my favorite mountain! I plan to share with my fellow Pilchuck-enthusiast-friends who will no doubt appreciate the insights:)