They are not ordinary edible mushrooms, they could be shaggy ink caps, which are edible, but be careful. Ink caps grow on buried rotten wood and have black gills underneath. If you leave them to mature the edge of the cap becomes 'shaggy' and breaks down into a runny, black, inklike material. The Bank of England used them for a while in the ink in banknotes, you could see the spores under a microscope and as long as they kept the secret of what they were using it made them un-forgeable.
The best rule with any fungi, if in doubt, don't eat.