Thanks, Adam...
I had missed that one.
I have seen fantastic video of CO2 disposal experiments, pouring globs of liquid CO2 onto the sea floor and seeing if it forms hydrates or not. In the experiment I watched, I think things were at a different depth and the CO2 was denser than water. (liquid CO2 is more compressible than water so at depth it shrinks and sinks)
There's always something new under the Sun (or in this case, WAY under it, since we're in the Mariana trench!)
I wasn't aware there were any natural occurences of liquid CO2 on Earth, but there you go!