Like the spark plug found in a coal steam in Australia?
I think they call stuff like that ‘OOPArts’ - ‘out of place artifacts’, q.v.
Like the spark plug found in a coal steam in Australia?
The identity of the geologist and the means of dating were never clarified, nor were the findings ever published in any known periodical.[1] Furthermore, at the time of the artifact’s reported discovery there was no method for dating the concretion.[4] There are examples of accretions surrounding iron or steel artifacts, some of them discussed by J. M. Cronyn. [5]
Stromberg accepted and also arranged for the artifact to be inspected by a geologist from the University of Washington Earth and Space Science department. The inspections confirmed the previous conclusion that the artifact was a 1920s-era Champion spark plug
https://en.wikipedia.org/wiki/Coso_artifact