Get ready to travel back in time, 24,000 years ago, to discover what Ohio looked like and the ancient animals that roamed the land.
As you follow this 1.2-mile loop around Lake Isaac, choose your favorite spots to stop and learn about the ancient history hidden on the trail.
Your journey begins at the Lake Isaac trailhead. Lake Isaac is glacial pothole, a unique feature in the landscape made thousands of years ago, when ice covered everything we stand on.
Around 70,000 years ago, ice started to build up in northern Canada. This sheet of ice grew to be about a mile thick at its highest points – that’s 5,280 feet! Imagine, where you are now, standing at the foot of the glacier and looking up to see only ice. This huge glacier, called the Wisconsin glacier, moved south from Canada very slowly, but reached Ohio around 24,000 years ago. This enormous glacier covered all but the most southern parts of Ohio before it slowly started to melt over the course of 10,000 years. As it moved, the glacier dug deep valleys into the earth underneath, turning over soil, and even moving rocks hundreds of miles with it. A “glacial erratic” is a rock that has been moved from the place it was formed by a glacier. In Ohio, many of our glacial erratics are large, igneous rocks, like granite, that were formed over 2 billion years ago by ancient volcanoes in Canada. While some glacial erratics are just tiny pebbles, others are massive boulders, over ten feet wide and weighing over 2,000 pounds!
By the time the Wisconsin glacier left Ohio, 14,000 years ago, the earth underneath the ice had changed completely. As the glacier melted, water came rushing out over the land. It filled in the valleys and grooves that the moving glacier left behind, creating rivers, ponds, wetlands, and lakes. Before the Wisconsin glacier, Lake Erie didn’t exist. There were two large, ancient rivers, one in the south called the Teays and one in the north called the Erigan. While some parts of the Teays’s valleys still exist in southern Ohio, the Erigan was completely destroyed by the movement of glaciers over thousands of years. Its valleys were deepened and filled with glacial meltwater, forming the young Lake Erie.
Lake Erie was originally nearly 500 feet deep, but gradually sediments filled in the bottom, and today, Lake Erie is only 210 feet deep at its deepest point, averaging closer to 60 feet. Lake Erie in its current form is less than 4,000 years old. The lake is one of our greatest resources in Ohio – the reason that Cleveland exists today – and it would have never been created without the movement of glaciers. By the time the Wisconsin glacier retreated, much of the waterways and terrain of Ohio was formed into what we see today.
If you stood in this spot 11,000 years ago, some of the animals you’d see would be very familiar. At the end of the Ice Age, many common Ohio mammals already existed, including foxes, raccoons, squirrels, minks, and porcupines. Some of the wildlife would look familiar, just much larger than their modern relatives. Fossils of giant beavers have been found in several places in Ohio; it looked a lot like today’s beavers, but they were about the size of a black bear! Other massive mammals that called Ohio home were the ground sloth, which were over ten feet long; the short-faced bear, which was over six feet tall; and the famous mastodon, which was slightly smaller than the modern African elephant. Even though no fossils have ever been found of them in Ohio, it’s likely that saber-tooth tigers and large dire wolves also lived here, since they were common in the states that surround us.
However, as the Ice Age ended and the climate quickly started warming up, the land around these animals started to change. Deciduous trees, like the oaks and maples that surround us today, quickly overtook the large spruce trees and other cold-climate plants. This abrupt change of plant life is thought to be what led to the extinction of these large, prehistoric animals.
Animals weren’t the only creatures roaming the ancient Ohio land. Towards the end of the Ice Age, early humans were coming to America. It is likely that many of these groups of hunter-gathers, known as Paleoindians, walked across the Bering Strait, when sea ice would connect Asia to North America. These groups were led by men and women who were well respected for their hunting or healing abilities. Paleoindians would hunt animals, everything from small fish and rodents to large mastodons; they would also gather nuts and berries. They would shelter in tents made from animal skins and bark, which were easy to take down and travel with, since they were also moving.
While few skeletal remains have been found of these early people in Ohio, we know they lived here because of signs they left behind. The most important artifacts found have been arrowheads from spears made of flint, a very important resource for the Paleoindian people. The distinct shape of these arrowheads make them easy to identify when they are discovered, and let us know that humans were in Ohio as early as 9,500 years ago.
As you come back to the parking lot, look over Lake Isaac, which now serves as a highly quality habitat and wildlife sanctuary for many of Ohio’s modern mammals, reptiles, and birds. As you learned earlier, Lake Isaac is a glacial pothole. This sort of feature was created as the Wisconsin glacier melted. As water starting draining, it began to swirl, like a whirlpool, picking up rocks and dirt as it did so. This swirling debris slowly started drilling down into earth underneath it created a “pothole.” Sometimes, these are also called “giant’s kettle” because they have smooth, even sides that makes it look like a large pot if it was empty. While it may look like a very ordinary body of water, Lake Isaac is a sign of the way Ohio has changed over thousands of years, and a reminder of the ancient history that surrounds us every day.