How was Niagara Falls formed?

It was formed by the Wisconsin glaciation ending about 12,000 years ago. Basically, a massive ice sheet retreated, and the meltwater carved out the Niagara River, which then flowed over the Niagara Escarpment—a hard cap of dolomite limestone over softer shale. The water erodes the soft shale underne

Report F000014. Filed.