What the Ice Left Behind

Everything you're going to look at today was made by ice, and fairly recently — so let me give you the short version, because it makes the whole peninsula legible.

Twenty thousand years ago you would be standing under a mile of glacier. Not near one. Under one. The Great Lakes basins are the grooves those ice lobes gouged out as they ground south, and the hills around you are what they shoved ahead of themselves and dumped when they stopped — piles of clay, gravel and boulders called moraines.

Then, about eleven or twelve thousand years ago, the ice let go. Meltwater filled the basins, the land itself began slowly rebounding upward now the weight was off it, and the lakes drained and refilled at different levels several times before settling where they are.

Which explains three things you'll see all day. The long parallel ridges of the peninsula are moraines. The inland lakes — Glen Lake, Crystal Lake, Lake Leelanau — are drowned valleys or hollows left where buried ice blocks melted out. And the odd flat terraces partway up some hillsides are old beaches, from when the lake stood much higher than it does now.

So the scenery isn't ancient in the way mountains are ancient. Geologically speaking, this landscape is about a week old, and it is still settling.