I recently dove with a local long time cave diver in Madison Blue. We went through Potters Delight and Rocky Horror and on back a ways. It was my first time in the system and he filled me in before and after the dive on the history of the system and how it has changed over time...I remember particularly his comments on the Potters Delight portion. The technique he explained was to use no leg or fin - just pull and glide off the side walls as this is fairly restrictive and there is beautiful clay on the bottom and we want to leave it there. On passing through I could see how over the years, divers passing through had scrapped, rammed, dug, or brushed against the bottom and "liberated" the clay into the flowing water, soon to become part of the "downstream"...it is hard not to. It took millions of years for those clay beds to form - and just a few to wear them away. With just a careless flip of your fin - drag of a reel - and a host of other small attacks on the cave - we wipe away history. WE are the enemy of the cave...WE have the biggest impact on the cave...and that is one reason we should all spend most of our time in the cave thinking about how not to damage it...aside from reducing visibility to where it might harm yourself or others...particulate in the water, reduced vis and worst case, siltouts...generally mean - you just harmed the cave...
Try looking between your legs and see what you are doing to the cave on your next dive - for most of us, it usually is a real learning experience.
To answer the question and not hijack too much...I was in Peacock and screwed up and lost bouyancy control doing a tieoff for a jump - finger poked quite gently to above my wrist into the silt - soft stuff, and I certainly did not feel a hard bottom under my fingertip - gently inflate and extract ones deflated ego from the cave floor and move on...happens - and part of the cave paid the price. There are many places I have seen silt dunes that were obviously many many feet deep.
