"Anne and her family lived alone on an island. She enjoyed having tea time with her friends the spiny lobster and baby hawk." National Geographic, August 1938
You never know what will turn up. I found these images while doing research for my novel -- by the way, it's NOT about a girl who lives alone on an island! But but the rock behind her figures prominently in the story. It is almost 3 billion years old, far older than these circles of it:
The Lewisian Gneiss Stone Circle at Callanish on an Early Autumnal Morning, Isle of Lewis, Outer Hebrides, by Lizzie Shepherd .... her other images are amazing, too, and well worth looking at full-size!
It's called Lewisian Gneiss, pronounced "nice." It comes in different colors, but is (usually? almost always?) striped:
Okay, back to work! It's hard to draw the line sometimes between time-wasting and research, but I THINK I'm getting better at it. Maybe one way is to stop once you've found out what you really need to know and save the rest for later?