A couple weeks ago, I was walking along a beach at Camano Island. The beach is below some bluffs of advance outwash sand and capped by till. There's more to that story, maybe later. There were a few cool rocks that had dropped to the beach from the bluffs, probably out of the till. Here's one rock that perfectly illustrates relative age dating and the principle of cross-cutting relationships. Basic geology 101, right? #geology #rocks #agedating #crosscuttingrelationships #relativedating