Pretending not to hear the unflattering remarks, Jason bent over the bomb and made a new hole in the clay seal.

It first appears c. 4 000 years ago on the clay seals of the Indus Valley Civilization.

The clay seal as a proof was therefore not convincing enough.

Petrie was also confused by the small number of clay seals.

I was extremely fortunate in discovering a clay seal in good condition that I suspect is several hundred years old.

And that, in turn, the design was imprinted on the fabric by a large clay seal.

While building the gravel sewer beds, construction crews broke through the clay seal, breaching the canal walls.

Other finds included a clay seal with a perforation and suspension on the reverse.

There they remained undisturbed until now, and the clay seal was so tight that a surprising number of wooden artifacts survived.

The first hint of them in the Middle East is on clay seals, dated a century or two later.