Petrified alligator turds.
Called copralites.
Alex.
That water seemed awful cold for alligators.
By the way, speaking of the tram ride back to the parking lot, which was always a well-buzzed experience, that reminds me of one time we saw a beaver along the riverbank during our float. So on the way back on the tram, with a family with kids sitting next to us, we started in with every stupid double entendre we could think of about the beaver we saw.
"Did y'all see that beaver cooling off in the river?"
'Yeah, that was a hot little beaver!"
"Well after it jumped in the river it was a hot, wet beaver. Did you see how furry it was?"
"Oh yeah, that was one hot, wet, hairy beaver. Did y'all get close enough to smell it?"
"Yep, that hot, wet, hairy beaver smelled like fish!"
Etc., etc., etc.