Today’s deskcrop is a bit of a puzzle. I collected this cobble on a beach on Great Cranberry Island, Maine. What caught my eye were the igneous crosscutting relationships. Take a look and see how many episodes of magmatism are indicated by all of the crosscutting relations. Beyond the crosscutting relations, see if you can also figure out all of the other geologic events that this rock has experienced. If you’re up to the challenge, write the geologic history of this clast in the comments.