When water levels restrict my access to the few river localities I'm familiar with, I like to go to the Yankeetown Spoil islands to look for echinoids. It's a different and very enjoyable place to spend a couple hours.
These islands were created by the dredging of limestone to deepen the adjacent channel. The "beaches" are a combination of lower Ocala limestone cobbles, rounded by wave action and sand. I've lately been interested in finding decent examples of the sand dollar Periachus floridanus which is very common in the lower Ocala, but because it is so large and thin, it rarely survives exposure to the elements and wave action. I started looking at the beach cobbles for traces of more complete samples.
The goal, obviously, is to find the cobbles with just a hint of sand dollar periphery so the damage to the specimen is minimized. Then with a dremel engraver, scrapers and stainless wire brushes, remove the soft limestone to expose the prize. Sometimes easier than others. Sometimes luckier than others. But entertaining and a worthwhile way to spend time while the rivers go back down.