While backpacking with my wife near the Napeequa River this summer I spent a night near a relatively unique feature in the Cascades, a cannonhole. In the morning I scrambled up near it and took the photo posted below. It wasn't huge but at least 15' across, maybe more.
I'm curious how many more of these exist in the Cascades. A large one near Dome Peak is pretty well know and is featured in the Kearney Guidebook. The Pillar of Pi, if not a cannonhole, is certainly an oddity.
John Scurlock seems to be aware of quite a few. I've paraphrased part of e-mail from him below.
"Dome,
Jack,
Snowfield (has two),
Bear (two also),
Arches (up near Arriva),
Silver Star,
and a couple others that don't come to mind just now."
If anyone has photos of these or knows of others I'd be interested in hearing about them.
This is found on the high ridgeline seperating the Napeequa River from the north side of an unnamed valley dropping down from High Pass.