![The Project Gutenberg eBook of Encyclopædia Britannica, Volume XVII Slice II - Luray Cavern to Mackinac Island. The Project Gutenberg eBook of Encyclopædia Britannica, Volume XVII Slice II - Luray Cavern to Mackinac Island.](https://www.gutenberg.org/files/43254/43254-h/images/img167.jpg)
The Project Gutenberg eBook of Encyclopædia Britannica, Volume XVII Slice II - Luray Cavern to Mackinac Island.
![The Project Gutenberg eBook of Encyclopædia Britannica, Volume XVII Slice II - Luray Cavern to Mackinac Island. The Project Gutenberg eBook of Encyclopædia Britannica, Volume XVII Slice II - Luray Cavern to Mackinac Island.](https://www.gutenberg.org/cache/epub/43254/images/img240d.jpg)
The Project Gutenberg eBook of Encyclopædia Britannica, Volume XVII Slice II - Luray Cavern to Mackinac Island.
![The Project Gutenberg eBook of Encyclopædia Britannica, Volume XVII Slice II - Luray Cavern to Mackinac Island. The Project Gutenberg eBook of Encyclopædia Britannica, Volume XVII Slice II - Luray Cavern to Mackinac Island.](https://www.gutenberg.org/cache/epub/43254/images/img246a.jpg)
The Project Gutenberg eBook of Encyclopædia Britannica, Volume XVII Slice II - Luray Cavern to Mackinac Island.
![The Project Gutenberg eBook of Encyclopædia Britannica, Volume XVII Slice II - Luray Cavern to Mackinac Island. The Project Gutenberg eBook of Encyclopædia Britannica, Volume XVII Slice II - Luray Cavern to Mackinac Island.](https://www.gutenberg.org/files/43254/43254-h/images/img178c.jpg)