Complex sentence: Sometime in the Uruk III period the massive White Temple, was built atop of the ziggurat, and under the northwest edge of the ziggurat an Uruk VI period structure, the Stone Temple, has been discovered.
Split into simpler sentences: Sometime in the Uruk III period the massive White Temple was built atop of the ziggurat. Under the northwest edge of the ziggurat an Uruk VI period structure, the Stone Temple, has been discovered.