Today's mountain, hills and sedimentary rocks were formed in Mesozoic era, Secondary epoch of cretaceous period.
The Mesozoic era began 252.2 million years ago following the Paleozoic era and it ended 66 million years ago at the dawn of Cenozoic era. A large percentage of the rocks found in Mesozoic era were sedimentary rocks. The fragmentation of the continents on earth began around the end Triassic period. As the continent rifted and separated apart the thick sequence of marine sediments accumulated in large linear an formed mountains.