You are looking for a small clip-lock box in a camo bag.
This cache was placed to celebrate 65 years of Mensa (the high IQ society) on 1st October 2011 and was part of a competition which has now closed.
Now just a standard traditional cache hidden in the Warwickshire countryside near to Stratford-upon-Avon. Walk a bit further down the path and you will reach the River Avon as it flows on it's way.
Cache placed with the kind permission of Groundspeak.