Side A: Thompson Ledges. Due to what is known as the Sharon Conglomerate or pebbly sandstone, these ledges have played an important role in the daily life of local residents and the economy. The porousness of this rock, which underlies much of Geauga County, supplies most of the county's drinking water. Thompson Ledges also provided building stone with stone cutters working in quarries turning out doorsteps, watering troughs, gateposts, culverts, and bridges from mid-1800 to 1911 for use in Thompson, Geauga County and occasionally beyond. After 1900, cement became the preferred building material, but still used silica pebbles from the Ledges for gravel and cement. The Ledges have an unusual ecosystem containing several distinctive forests. A chestnut oak forest is pervasive on the top while a northern hemlock forest exists in the exposed creaks and crevices of the upper rim and ledges. Side B: Thompson Ledges Park. Thompson Ledges have long been known for their natural beauty, with caverns, fissures, springs, and a striking view. The area was known to early setters and explorers, but has been a popular tourist and picnic area since the 19th century. This attraction encouraged the Thompson Township residents to create, by vote, one of the county's earliest parks. The project began in 1926 with the idea that the Ledges would become a part of a larger state park. Even though strongly supported by state legislators, the Great Depression of 1929 and the downturn in the economy delayed the project until 1940. Thompson Ledges Park became an official township park of 13 acres on January 31, 1941. The park grew to 66 acres in 1999.