Ruminate Stones

[larryours]

Has anyone found any ruminate stones in the deer's stomach, they've killed ?
Years ago I had an older hunter(older than me) tell me that over the years he had found a few stones in the deers stomach, they form in the deers stomach( much like a kidney stone in humans) only they form in the deers stomach. I've tryed to find some over the years, after I gut a deer, cut open the stomach and with a stick search the contents, no luck ! Has anyone else heard/ or found one of these stones ?