
Here's a little more detail on the islands:
#1 Isle Royale _ on Lake Superior.
#2 Ryan Island _ on Siskiwit Lake.
#3 Vernal pond _ on Ryan Island.
#4 Small boulder _ in vernal pond on Ryan Island on Siskiwit Lake on Lake Superior.
~ Clear as mud Ay' ~
Worlds coolest island turtle on that day perhaps .
https://maps.app.goo.gl/5sWM6ZGueL9LQa7e9This incredible natural phenomenon exists on Lake Superior, which is the largest freshwater lake in the world. Within this massive lake lies Isle Royale, a large island surrounded by the clear waters of Lake Superior. But the story doesn’t stop there. On Isle Royale, there is another smaller lake called Siskiwit Lake.
Inside Siskiwit Lake, there is yet another island, known as Ryan Island, and on this island, there is a small pond that holds a little boulder.
When the pond on Ryan Island floods, this boulder essentially becomes the smallest "island" on what could be considered the most layered island setting in the world. It’s an island within a lake, on an island within another lake, on the largest island in the largest freshwater lake on the planet. This layered structure is a fascinating example of how complex and unexpected nature can be. It’s like a natural nesting doll, showcasing the wonder of our world’s geography in a simple, yet mind-bending way.
I can't find the small pond on Ryan Island with a little boulder in it on google maps, but I have no doubt there is a little seasonal / vernal pond on Ryan Island with a little boulder in it. 
So if there's a turtle on that boulder he/she is in a very unique place on the planet and doesn't even know it.

BTW Clynn if you're thinking about heading to Ryan Island it is
not a "for the faint of heart" kind of place to get to at all.
I suppose we could cheat and take a float plane with canoes/kayaks to Isle Royal, but even from the 3 legal landing sites it quite the paddle/portage adventure to Siskiwit Lake and then on to Ryan Island. From there the "finding" begins.
And ain't no one saying exactly where the vernal pond on Ryan Island is exactly.
Ryan Island is also a trail less bushwhack island and it's about 39 Acres in size.

You know me. Now I wanna go .
https://www.fodors.com/world/north-america/usa/michigan/experiences/news/what-its-like-to-paddle-solo-to-the-largest-island-on-the-largest-lake-in-the-world