I am doing a workshop for a local event called Day of Insects. My workshop is actually on March 23, 2018, a day prior to the main event. I am no kind of expert on snails, but I am an enthusiast. I have photographed a few of the terrestrial snails and can work through the identification process. I will do my best.
Today I walked along the shores of Saylorville reservoir and found a small bag full of snail shells. Most represent terrestrial species, but I did see a few aquatics.
Not much scientific value to these shells. They are heavily bleached by the sun. Also, they almost certainly did not originate from the location they were found. The light shells are easily washed downstream, so some could have originated miles from where I found them. Still, I was somewhat surprised by the diversity I found with little effort.