Read about this earlier, much higher photos can be found below. http://www.thehistoryblog.com/archives/55136 Still pretty neat.
I hope the local authorities don't decide to buy up the entire hoard just so it can sit in some museum basement for the next 30-40 years until someone decides they need money for a project and sell them all off. It would be nice to see at least 25% of the hoard make it into the marketplace soon. If it's dated to around 307AD, it's probably common pre-Constantine London Mint coins, mixed with tetrarchy coins from other parts of the empire, and maybe even a few Probus, Carus, Numerian, and Carinus thrown in for good measure.