Googling around using the phrase, "Grand Traverse Bay," I found the photos above by Robert Charity ( www.pbase.com/bobc/image/83933534 and http://www.pbase.com/bobc/image/83954564).
And then these 3 above, by Matt Callow who captions the first one with: “… took a lot of pictures of the glacial erratics scattered all over the area. This is on the Lake Michigan shore near Pyramid Point, and that's one of the Manitou Islands in the background, South Manitou I believe.”
But last and not least, the photos by Chris Doyal of the Archaeologist Dr. Mark Holley and Mastodon Stone in Grand Traverse Bay, MI. He calls it " the almost famous Michigan Mastodon Petroglyph Stone." He asks not to reproduce them without written permission, so click here: