Right in the heart of Houston is a history lesson you can study with a paddle.

“It amazes me that this is in the middle of our city,” says Tom Helm. “Geologically, we can tell it’s been there for at least 12,000 years. That was the end of the last ice age.”

Helm’s a geologist by day and a canoer whenever he can. On Buffalo Bayou, his two passions combine.

“Right here on the right, you can see some of these layers, rock layers right there,” he says, pointing to the banks.

That rock is sandstone, part of the Beaumont Formation, and you can spot it along most of our 17-mile route. In it, you’ll find hints of the bayou’s past, like an old riverbed embedded in the current one.

“It looks to me like some older form of Buffalo Bayou that was deposited there sometime in the past,” explains Helm. “Now modern Buffalo Bayou has cut through that.”

WATCH: Buffalo Bayou's hidden wilderness

Some outcroppings suggest an even more extreme change from the landscape we know now.

“Over the past 100,000 years as sea level has gone up and down, there have been times when we had a more marine-type setting, like what you see at the head of Galveston Bay now,” he says.

That means Galveston Bay was, at one time, in Uptown.

“This is another bit of evidence that the bayou’s been here for a long, long time,” adds Helm.

To learn more about canoeing on Buffalo Bayou, click here.