Jay Stottman (a.k.a "Privy Boy") forgot to mention that in those
excavations of the cesspool (and privies) we used a method that
was, as far as I know, developed by him where a back-hoe prepared
a block-style excavation around the feature, with shored/stepped
walls to OSHA standards, and we attacked the nasty things from
the side.  The caveat here is to fully excavate the area around
the feature prior to using the heavy guns.  The faunal assemblages
from these deposits may be the most wonderful things!
Jeff Watts-Roy