Taken from inside the First Cave, looking out.
In the background,  the
cypress log can be seen.

That log was placed there many years before, but I never learned who placed it, or why.
The log provided a handy place to anchor the large inner-tube that we placed over the "boil".

This is a re-breather scuba system SEALAB tested in Morrison Spring.

Notice there are no bubbles!

Mercury Seven Astronaut/SELAB Aquanaut Scott Carpenter made many dives at Morrison Spring during the six years that SELAB tested equipment at the Spring. 
My dad was especially proud to be presented with that autographed picture.