Exodus 2:3

Ark of bulrushes] a chest made of the stalks of the papyrus reed which grew at the side of the Nile and in marshy places. The stalks and leaves of papyrus were employed in the manufacture of various articles, such as boats (Isaiah 18:2), sails, mats, ropes, and paper. This last, which gets its name from the papyrus, was made of thin strips of the inner bark pasted together, and compressed. The slime used as a watertight coating for the ark was bitumen, imported into Egypt from Mesopotamia and the vicinity of the Dead Sea; it was employed as mortar in building and as a preservative in the process of embalming.