The ridge-like deposit of sediment at the edge of a glacier is called a terminal moraine.

Here's a breakdown:

* Moraine: A general term for any accumulation of rock debris carried and deposited by a glacier.

* Terminal moraine: Specifically refers to the ridge of debris deposited at the furthest point a glacier has reached. It marks the glacier's maximum extent.

Think of it like the "high water mark" of a glacier, showing how far it once extended.