The Niagara is a fairly young river, only 12,000 years old!, a microsecond in geological time. The Niagara Escarpment, which was created by erosion is much older.
After the last ice age when glaciers pressed down on the area, the slow process of erosion by ice and water has created this escarpment.
The mighty river plunges over a cliff of dolostone and shale. Dolostone is a sedimentary carbonate rock that contains a high percentage of the mineral dolomite. Most dolostone formed as a magnesium replacement of limestone or lime mud prior to lithification. It is resistant to erosion and can either contain bedded layers or be unbedded. Shale is a rock formed from fine grained muds and clays. It is characterized by thin laminae breaking with an irregular curving fracture, often splintery and usually parallel to the often-indistinguishable bedding plane. This property is called fissility.
Niagara Falls is the second largest falls on the globe next to Victoria Falls in southern Africa. One fifth of all the fresh water in the world lies in the four Upper Great Lakes-Michigan, Huron, Superior and Erie. All the outflow empties into the Niagara river and eventually cascades over the falls.
Please note that the posted co-ordinates will bring you to Table Rock near the brink of the falls, but you will still have to look around a bit for the required information. The plaque you are looking for is located at N43 04.861 W79 04.693
To Log a find on this beautiful scenic earthcache you must email us with the dimensions listed on the historic plaque along with the most recent date of rock fall. We'd love it if you could also take a picture of yourself/team with gps in hand ,standing with the Canadian Horseshoe Falls behind you and post it with your find log (please no spoiler).