The boulder behind Mount Baker Theatre is rather conspicuous. Nestled in the alley behind the building between Commercial and Unity streets, it looks like city planners made a mistake.

But no, this boulder is not an interloper. The outcropping is Chuckanut sandstone, the local geologic formation that makes up the Chuckanuts and the rest of Bellingham's hills and coastline, running below the buildings and streets of downtown.

The Chuckanut sandstone formation was deposited 50 million years ago, before the formation of the Olympic Mountains.

https://www.cascadiadaily.com/news/2022/nov/09/whats-the-deal-with-mount-baker-theatres-boulder/