COLLISION OF CONTINENTS. The history of the landscape reaches back to the lower Devonian (about 400 million years ago). Europe and America formed a single continent called Laurussia. The continent Gondwana, consisting of Africa, India, Australia and the Antarctic was located south of Laurussia. During this period, the low mountain range called the Rheinische Schiefergebirge was actually a shallow ancient sea. Rivers brought huge amounts of sand and clay into this sea basin. Coarse sand was deposited nearer to the coast while clay was transported far out into the sea and deposited as mud. As the seafloor slowly sank, the sediments accumulated to thicknesses of several kilometres. At the end of the Devonian, both continents drifted towards each other until they collided. During the collision, these sediments were overthrusted and folded - forming a large mountain range that rose above the sea.
     The impressive relics of these events are seen in the steep dip, folding and foliation of these ancient rocks. The slates are the characteristic rock of the Rheinische Schiefergebirge low mountain range. As the sediments were subjected to high pressures during the mountain building process their structure was changed. This „metamorphosis“