The most striking feature in the temple-area, which was uncovered in the course of the excavations, is the great temple-tower, or ziggurat, erected by Ur-Engur, and faced by him with kiln-baked bricks bearing his name and inscription.[2] The ziggurat in its later and imposing form was built by him, though within its structure were found the cores of earlier and smaller towers, erected by Narâm-Sin and during the pre-Sargonic period. In fact, Ur-Engur considerably altered the appearance of the temple. In addition to building the ziggurat, he raised the level of the inner court above Narâm-Sin's pavement, and he straightened the course of the outer wall, using that of Narâm-Sin as a foundation where it crossed his line. His wall also included mounds XII. and V., in the latter of which many of the temple-archives have been found. During the Kassite period these were stored in buildings in mound X., across the Shatt en-Nîl in the area included within the inner city during the later periods. An alteration in the course of the river from the north-east to the south-west side of the temple area probably dates from the period of Samsu-iluna, who upon a cone found in _débris_ in the temple-court records that he erected a dam and dug out a new channel for the Euphrates. His object in doing so was probably to bring a supply of water within reach of the later extension of the city on the south-west side. The excavations on the site of Nippur and its temple have illustrated the gradual increase in the size of a Sumerian city, and the manner in which the temple of the city-god retained its position as the central and most important building. The diggings, however, have thrown little light upon the form the temple assumed during periods anterior to the Dynasty of Ur. In fact, we do not yet know the form or arrangement of an early Sumerian temple; for on early sites such as Fâra, Surghul, and Bismâya, the remains of no important building were uncovered, while the scanty remains of Ningirsu's temple at Tello date from the comparatively late period of Ur-Bau and Gudea. On the latter site, however, a number of earlier constructions have been discovered, and, although they are not of a purely religious character, they may well have been employed in connection with the temple service. Apart from private dwellings, they are the only buildings of the early Sumerians that have as yet been recovered, and they forcibly illustrate the primitive character of the cities of this time.