Complex sentence: The exact history and development of the Ullapara region is not known, but according to most geologists, in 4500 B.C., the land of Varendra was built with parts of Dinajpur, Joypurhat, Bogra and Rajshahi and the west parts of Pabna.
Split into simpler sentences: The exact history and development of the Ullapara region is not known. But according to most geologists, in 4500 B.C., the land of Varendra was built with parts of Dinajpur, Joypurhat, Bogra and Rajshahi and the west parts of Pabna.