The unknown object is buried approximately 300 feet below the shattered remains of the once great city of Ur. After the coming of Yog-Sothoth, the Beyond-One, nothing remains of the utopian culture that once thrived there. It is not clear what terrible evil precipitated the arrival of the son of Azazoth to Ur, although legend says the evil act was 600 times greater than normal. In an attempt to stop the being known by the vaporous brains of the spiral nebulae as an untranslatable sign, the inhabitants of Ur had surrounded the city with a ring of salt some 200 miles in diameter. Unfortunately, as Yog-Sothoth knows all and sees all, and is coterminous with all of time and space, the Eldritch magic was totally ineffective.
Authors note: The clues are in the italicized terms above. Yog-Sothoth is actually a microscopic artifact I observed while scanning through a sample on my inverted phase contrast microscope. I believe it to be a conglomeration of detritus and precipitated salts. The image was taken at ~600X magnification under regular contrast with no stain.