I found this in Ossett, West Yorkshire, UK recently and it is carboniferous In age. The one which is visible is another one which I am going to glue on, but it was not found like that. The place in the rock where it is is actually where a negative cast is, but the other nut I found before fits in perfectly. I cracked some of the matrix off and it contained another trigonocarpus nut. Could it contain even more?