It is probably a Trigonocarpus nut.
http://www.fossilsforsale.co.uk/plantsfernsseeds.htm (incl. prices)
Thanks for the reply. I have looked at trigonocarpus nuts on the internet and this it definietly one. I found this in a soft sandstone, and it was removable by hand. Does something have to be a fossil to be in soft sandstone?
Sandstone may be soft because:
- it has not yet been fully lithified (ie. it is in the process of turning from sediment to sedimentary rock)
- it has been partly decomposed (that can happen when the cement or sedimentary particles or both become unstable due to a change in physical/chemical conditions)
So a specimen in a soft sandstone may be a fossil or subfossil, as per one of my replies to one of your other recent posts. If it is in a sandy sediment (not yet a sandstone), it is still not a simple answer, because it could be modern specimen (not a fossil) or a lump of old stone which happens to be a fossil.
Clear as mud?!