While looking for an old post on Palau diving (which I didn't find), I
came across this:

Date:         Wed, 3 Oct 2001 20:03:18 -0500
Sender:       SouthEast US Scuba Diving Travel list
<SCUBA-SE@RAVEN.UTC.EDU>
From:         Mike Wallace <mwallace61@HOME.COM>
Subject:      River Dive
I'm headed up to South Carolina Friday for my second shark tooth
dive in the Cooper River just outside of Charleston. For any of you
east coasters that haven't done this I highly recommend it. It is black
water diving in some pretty rockin' current but a lot of fun too. Last
trip had about a 90 minute bottom time and brought home 30 some
odd teeth between my son and I. Only crapped the suit once when I
thought the log I touched moved. This one wasn't a gator but
definitely could have been. :-)

That's NOT the Mike Wallace of 60 Minutes investigating the
pre-historic
sharks, but the Huntsville, Alamaba Wallace.

The black waters of Cooper River in South Carolina is well-known for
the river dive Mike was talking about.  Even though I lived in SC
for years until I retired, I couldn't say "been there, done that",
because anything less than 50-feet visibility is rotten diving.  :-)

But I did dive in the Crystal River in Florida while I was a clueless
newbie.  The vis there was great, but you couldn't see far from the
crooks and turns of the shallow river.

-- Bob.