A National Natural Landmark, the Glacial Grooves on the north side of Kelleys Island are the largest easily accessible such grooves in the world and are accessible daily in season, weather permitting, via the Kelleys Island Ferry departing from Marblehead. From a walkway, footbridge and stairs you can look down on the immense grooves, which are 400 feet long, 35 feet wide and up to 10 feet deep, suggesting the tremendous power of the ice that formed them. Average visit time: Allow 30 minutes
Of Devonian limestone, Glacial Grooves Geological Preserve contain marine fossils that are 350 to 400 million years old. They were scoured into solid limestone bedrock about 18,000 years ago by the great ice sheet which covered part of North America.
Glacial Grooves Geological Preserveis locally managed by the Ohio Department of Natural Resource's Lake Erie Islands State Park.