Note that all of the mollusks photographed here were promptly returned to their home after the photograph was taken. These animals were found in June 2004. They prefer the silty/sandy part of the lake bottom and submerge themselves half way into the lake bed.
We found the shells shown below on May 4, 2010 on Jones Island Beach in the debris that has washed up there over the winter months. The shells were all located together at the south end of the beach. Leonard Dane of the Lake County Health Department Environmental Services has preliminarily identified these as Corbicula fluminea. These are an invasive species and are a threat to the native organisms in Grays Lake. Read more about them here: http://www.issg.org/database/species/ecology.asp?si=537&fr=1&sts=&lang=EN
On August 11, 2010 with lake water temps at 86 F (30 C), we felt smooth "rocks" with our feet at a water depth of 5 feet just 10 feet south of the roped swimming area on Jones Island. Lifting these "rocks" up revealed the first confirmed live Corbicula fluminea.
These shells were discovered by Kate in shallow water near the boat launch at the end of George Street on 7/18/11. They have yet to be identified.