I mention this area, not because I think you can find/dig geodes here, but this is a nice little place to have a picnic and at least check out the creek. This is the type locality for the Warsaw formation geodes, so if you are a location hunter, a geode from here is a must. The Warsaw shale with the geodes is located just downstream from the park. You cant miss it if you stay in the creek bed (assuming low water... best when dry). The geodes are nice with gemmy quartz but the shale is very enduring. Similar to the 'great wall' on the Fox river, rockhounds have busted off the tops of the geodes in situ, unable to chisel them out of the cement-like host rock. Up from this exposure on the east side of the creek, is an exposure of small, mostly-flattened 'Pandoras box' type geodes with pink calcite and numerous secondaries. This exposure only shows up occasionally however, after a flood has washed off the overburden. I could not find it when I was there in 2012, but I know it exists somewhere under the brush and weeds.
This creek has several bluffs made entirely of the Warsaw shale, and occasionally a geode will poke out its head in this mostly barren rock... but it is rarely of good quality. The good stuff is in the creek bed and right bank, just downstream from the shale bluffs. Good luck getting them out, I couldn't.
My first trip to geode park was a long time ago (I think Jimmy was president). I was there to find a 'type locality' geode and I was in a mood not to be denied. I chiseled and hammered and could not get a geode to come loose. Upstream, I had found the little pink calcite exposure, but the poorly formed geodes did not satisfy. I decided to walk this creek to its mouth at the Mississippi river for as long as I did not encounter a 'No Trespassing' sign. No signs were encountered and I found several nice geodes in the gravels of the creek a few hundred yards down from the mother load. Is this land part of the park? I don't know. It was all grown up with weeds and no sign of civilization. I have not ventured down the creek since that day as the geodes are good, but not great, and there are too many other exposures around Keokuk that have my attention.
I encourage you to check out this geode park and enjoy the little town of Warsaw, with its simple country charm. At one time, this river town was a very important port on the mighty Mississippi.