| The development of the Falls were caused by two main factors: 1. the lowest layer of the ground consisting of rocks, is much older than the Falls; 2. the latest geological movements during the ice age. The formation of the Rhine Falls during the ice age 500’000 years ago the glaciers moved from the alps downwards due to a drastic fall in temperature, and formed the landscape as it is nowadays. 1. original flow of the Rhine River approximately 200’000 years ago, before the start of the ‘Riss ice-age’, the Rhine River flowed from Schaff-hausen westwards through the countryside ‘Klettgau’. Afterwards this valley was filled up again with morai-nes.  |
| 2. the first change of the flow of the Rhine River approx. 120’000 years ago, during the ‘Riss ice-age’, the Rhine River turned to the south and formed the Rhine valley of the ice-age. The basin below the Falls is still the same old valley, filled with moraines. 
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| 3. the second change of the flow of the Rhine River and the beginning of the cataracts during the latest ice-age, called ‘Würmeiszeit’, the Rhine River was forced to change the route in a wide bow to the south and eventually reached a hard soil called ‘Malmkalk’ above the Falls. 15’000 years ago, right on the borderline where the soil changed from hard limestone to softer moraine, the cataracts were formed due to different erosion caused by the river. The remaining rocks are part of the original steep hard limestone.  |