Another Fungi, not really these are still mushrooms.
Here is a mushroom farm. Not much to see here but I will put up a like if your interested in the mushroom process in a place like this.
http://www.daff.qld.gov.au/plants/fruit-and-vegetables/specialty-crops/mushroom-production-methods
Mushrooms are grown by feeding the B___S__T and keeping them in the dark. Is this true or false?
The cache you seek will not be hard to find, be gentle when you extract the logbook so the hide isn't damaged.