This pitch covering was probably natural bitumen that was commonly found in seepages in the Middle East.
Yeah. Bitumen, the tarry fractions of petroleum found in seepages from rocks in the Middle East. Petroleum from living material that drowned in the Flood in rocks from sediments that were all buried by the Flood. Which hadn't happened yet.
Why isn't that real convincing?
And why are we worried here about the etymology of the
English word "gopher" when Genesis was written down in Hebrew a millenium and a half before the English or Old French languages existed?